Implantable system for stimulating a human heart or an animal heart

ABSTRACT

An implantable system for stimulating a heart contains a processor, a memory, a stimulator, and a first detection unit for detecting a cardiac rhythm disturbance of a cardiac region. The memory includes a computer-readable program, which prompts the processor to carry out the following steps: a) detecting via the first detection unit whether a cardiac rhythm disturbance is present in a cardiac region of a heart of a patient; b) when a cardiac rhythm disturbance is present, selecting a stimulation strategy based on a selection criterion; c) stimulating the cardiac region in which the cardiac rhythm disturbance was detected by way of the stimulator, using the selected stimulation strategy; d) detecting a success and/or an efficiency of the conducted stimulation; e) comparing the success and/or the efficiency to a predefinable success and/or efficiency criterion; and f) if the predefinable success and/or efficiency criterion was not achieved, optimizing the stimulation strategy.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of patent application Ser. No.16/835,638, filed Mar. 31, 2020; this application also claims thepriority, under 35 U.S.C. § 119, of German patent application DE 10 2019110 284.7, filed Apr. 18, 2019; the prior applications are herewithincorporated by reference in their entirety.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to an implantable system for stimulating ahuman heart or an animal heart, to a method for controlling theoperation of such a system, and to a computer program product suitablefor such control.

Implantable systems for stimulating a human heart or an animal heart,such as cardiac pacemakers, have been known for quite some time. Thesecan carry out a variety of functions. It is known, among other things,to use such cardiac pacemakers for treating atrial arrhythmia. Differentstimulation programs may be carried out by a corresponding cardiacpacemaker in the process so as to return the treated heart to a normalstate.

Frequently, it is difficult to predict which type of treatment is usefulfor adequately and effectively treating arrhythmia, and in particularatrial tachycardia.

U.S. Pat. No. 6,876,880 B2, for example, describes the option ofdifferent atrial pacing therapies being applied consecutively. The USpatent furthermore describes that the success of the treatment isdependent on changes of the atrial rhythm. As a result, the US patentfurthermore opens up the option of repeating atrial pacing therapiesthat were previously unsuccessful once a predetermined period of timehas passed or the condition of the heart has changed otherwise. In thisway, an improved treatment of atrial arrhythmia is to be achieved.However, this procedure yields only moderate success since ultimatelythis requires a spontaneous change in the condition of the heart or thepassing of a sufficiently long period of time.

In known implementations, so-called aATP (atrial antitachycardia pacing)pulses are delivered to the atrium so as to terminate atrial tachycardia(AT) or atrial fibrillation (AFib). It is known to synchronize an aATPtherapy with ventricular cardiac action in terms of time.

In other implementation examples of aATP, such as in U.S. Pat. No.6,876,880, aATP pacing pulses are applied when changes in AT or AFibrhythm are identified, or when changes in the cycle length of AT/AFibare detected, or when a preprogrammed time has elapsed.

One problem of the known implementations of the aATP therapy is that thetherapy is not sufficiently effective.

U.S. Pat. No. 7,107,098 B2 describes a method and a device forgenerating and selecting therapies, or hierarchies of therapies,suitable for treating atrial or ventricular tachycardia. It is providedto store an effectiveness of a therapy achieved in the past, and to thenassign a higher hierarchy to this therapy.

U.S. Pat. No. 6,393,321 B2 describes a method and a device fordelivering an atrial antitachycardia pacing therapy. The pacing therapymay be delayed if the presence of ventricular tachycardia is suspected.In particular, it is provided to use a delay timer so as to delay thedelivery of the atrial antitachycardia pacing therapy.

U.S. Pat. No. 7,280,869 B2 describes a method for determining whether atachyarrhythmia episode has been terminated. A heart beat pattern isused for this determination, which represents a sequence of atrial andventricular depolarizations.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide a cardiac pacemakerthat enables improved treatment of cardiac rhythm disturbances and has alower power consumption than the cardiac pacemakers known from the priorart.

It is a further object of the present invention to provide an optimallyeffective stimulation therapy for cardiac tachycardia which terminatesthe tachycardia long-term or prevents recurrence.

This object is achieved by an implantable system for stimulating a humanheart or an animal heart having the features described herein. Such asystem is intended, in particular, for the permanent implantation in ahuman patient or an animal patient.

Such an implantable system comprises a processor, a memory unit, astimulation unit, and a first detection unit for detecting a cardiacrhythm disturbance of a heart region.

According to the invention, it is provided that the memory unitcomprises a computer-readable program, which prompts the processor tocarry out the steps described hereafter when the program is beingexecuted on the processor.

First, it is detected by way of the first detection unit whether acardiac rhythm disturbance is present in a cardiac region of a heart ofa human patient or an animal patient. A presence of a cardiac rhythmdisturbance within the meaning of the present invention is to bepresumed if the onset or the presence of a cardiac rhythm disturbancecan be detected.

If such a cardiac rhythm disturbance was identified, a suitablestimulation strategy is selected based on a selection criterion. Theselection criterion includes a measurement variable or a variablecalculated from the measurement variable. The measurement variable isselected from the group consisting of a physiological measurementvariable of the patient, a pathophysiological measurement variable ofthe patient, and a non-physiological measurement variable indicating astate of the patient. In particular, the group available for selectionis composed of the above-described measurement variables or a subsetthereof. The selection criterion can comprise more than one of thesemeasurement variables, which can also be arithmetically related to oneanother. A different weighting of individual or all measurementvariables is possible.

According to one embodiment of the invention, the object underlying theinvention is achieved in that the condition of the heart is detectedprior to the aATP delivery. The condition can be mapped using differentparameters, which are described within the scope of the invention. Asuitable point in time for delivery of the aATP therapy, having a highlikelihood of success of the therapy, can be ascertained based on atleast one of these parameters.

Afterwards, the cardiac region in which the cardiac rhythm disturbancewas detected is stimulated using the selected stimulation strategy. Thestimulation unit is used for this purpose. The stimulation unit can bean atrial stimulation unit or a ventricular stimulation unit. It ispossible to stimulate one atrium or both atria and/or one ventricle orboth ventricles using the stimulation unit. The stimulation of thecardiac region or of the cardiac regions is carried out with theobjective of terminating the detected cardiac rhythm disturbance. Forexample, the cardiac rhythm disturbance can be atrialtachycardia/tachyarrhythmia (AT) or atrial fibrillation (AFib). As aresult of the selected stimulation strategy, ideally a stimulation iscarried out which results in a termination of the detected cardiacrhythm disturbance, such as the detected AT/AFib, within a short timeperiod, using the least amount of energy possible, and the terminationsuccess of which is long-lasting, that is, a long duration passes untilAT/AFib occurs again.

Thereafter, a success and/or an efficiency of the conducted stimulationare detected. This can take place by way of the first detection unitand/or a further detection unit of the system.

The detected success and/or the detected efficiency are now compared toa predefinable success and/or efficiency criterion. In this way, it ispossible to determine whether a desired success or a desired efficiencywas able to be achieved. A success of stimulation is, for example, thata normal heart rhythm is restored. Indicators for the efficiency of aconducted stimulation are, for example, the time required for restoringa normal heart rhythm, the energy required to do so, or also the timethat passes between the first AT/AFib termination and the renewedoccurrence of AT/AFib. If this time increases for successive AT/AFib,this speaks in favor of the effectiveness of the stimulation accordingto the invention.

If the predefinable success and/or efficiency criterion was achieved, noadaptation of the stimulation strategy is required. Rather, the selectedstimulation strategy is then already sufficiently successful orsufficiently efficient for the treated cardiac rhythm disturbance. If,in contrast, the predefinable success and/or efficiency criterion wasnot achieved, the stimulation strategy is optimized, so that bettersuccess and/or greater efficiency can be achieved during a subsequentstimulation using an optimized stimulation strategy. The optimization ofthe stimulation strategy includes a change in the stimulation strategywith respect to at least one parameter. This parameter is selected fromthe group consisting of a form of the treatment, a number of thetreatments, a combination of different treatments, a frequency of thetreatments, and a point in time of the treatment. In particular, thegroup is composed of the above-described parameters or a subset thereof.

The expression “form of the treatment” shall, in particular, beunderstood to mean a design and/or a pattern of electrical pulses thatare delivered within the scope of stimulation by the stimulation unit.

The point in time of the treatment can be selected in such a way, forexample, that particularly good success or a particularly highefficiency of the stimulation is to be expected. The reason is that astimulation which is delivered during a particular phase of a cardiaccycle can, in principle, have a higher success rate for treating acardiac rhythm disturbance than a stimulation which is delivered at adifferent point in time of the heart rhythm.

In one variant, the measurement variable is a hemodynamic measurementvariable of the patient, an amplitude of an intracardiac electrogram, anamplitude of a far field signal, an amplitude of an electrocardiogramsignal, an amplitude of an atrial signal, a systemic blood pressure, anarterial blood pressure, a venous blood pressure, a blood pressure inone of the ventricles, a pulmonary arterial pressure (PAP), anotherblood pressure, a change in one of the aforementioned blood pressures, achange in a morphology of a detected signal, an impedance change of adetected signal, a measurement value allowing a conclusion of aregularity or irregularity of the heart rhythm of the patient, a bodyposition of the patient, a contractility of the heart muscle, or thechange in the contractility of the heart muscle. As an alternative or inaddition, the measurement variable can also be a variable that indicatesor reflects one of the aforementioned variables.

A body position of the patient can, for example, be an upright position,a sitting position or a recumbent position (in particular a horizontalposition). By selecting one or more of the aforementioned measurementvariables, it is possible to take the current condition of the patientor the state of health of the patient into consideration in theselection of a suitable stimulation strategy. For example, if anincreased blood pressure of the patient is detected, a stimulationstrategy is selected which does not result in an increase in the bloodpressure, so as not to further increase the already elevated bloodpressure of the patient. Similarly, other physiological measurementvariables of the patient may be used to select the stimulation strategyin such a way that a deviation of the respective measurement variablefrom a standard value or a standard rang a predefined value and/or anindividual measurement value for the patient (for example a mean value,a median and the like) is not further amplified by the selectedstimulation strategy.

In particular when the measurement variable is a hemodynamic measurementvariable of the patient, it is provided in one variant that themeasurement variable can be ascertained by the implantable system itselfby way of the first detection unit or by way of a further detectionunit. It is not necessary then to provide an additional sensor unit fordetecting the measurement variable.

In another variant, however, such an additional sensor unit is provided,which is configured independently of the implantable system forstimulating the human heart or animal heart. Such an additional sensorunit makes it possible to determine not only hemodynamic parameters, butalso other physiological parameters of the patient particularly easily,so that the possible physiological, pathophysiological ornon-physiological measurement variables available for selecting themeasurement variable can be expanded.

In one variant, the efficiency of the stimulation is a physiologicalefficiency. In particular the duration that is required to successfullytreat an identified cardiac rhythm disturbance by way of the selectedstimulation strategy is a measure suitable for determining thephysiological efficiency. As an alternative or in addition, theefficiency can be a non-physiological efficiency, namely an efficiencyfor the energy required for the stimulation. Each implantable system forstimulating the human heart or animal heart comprises a power source,which contains a finite amount of energy. The service life of suchsystems decisively depends on the use of energy. If it is possible tolower the energy consumption, while keeping the success of the conductedstimulations at least the same, the service life of the stimulationsystem is increased. This is associated with considerable comfort forthe patient since a surgical procedure for replacing the stimulationsystem or the power source of the stimulation system is not necessaryuntil at a later time.

In one variant, stimulation strategies that in the past have proven tobe particularly promising or efficient for a particular type of cardiacrhythm disturbance are given a higher priority than other stimulationstrategies. When a renewed stimulation is carried out, thesehigher-priority stimulation strategies are then preferably selected forcarrying out the stimulation. In this way, stimulation strategies thatare expected to be successful can be predominantly applied. Thistypically increases the success or enhances the efficiency of theconducted stimulation. So as to carry out this variant, the programprompts the processor to store the selection criterion, the appliedstimulation strategy and the success achieved thereby and/or theefficiency achieved thereby in the memory unit. Thereafter, the storedstimulation strategy is prioritized as a function of the achievedsuccess and/or the achieved efficiency. This storage can take place, forexample, in the form of a ranking table, wherein stimulation strategiesthat are listed higher in the ranking table have a higher prioritizationthan stimulation strategies listed further down, and are givenpreference in a subsequent selection of a suitable stimulation strategy.Other types of prioritization or hierarchization of the differentavailable stimulation strategies are likewise conceivable.

So as not to carry out a treatment of a patient that is likely not verypromising or not very efficient to begin with, or so as to utilize theenergy available for the stimulations as efficiently as possible, it isprovided in one variant to entirely exclude a stimulation strategyhaving a low prioritization at least temporarily from the stimulationstrategies available for selection. For example, it is possible not tooffer such a low-priority stimulation strategy as a stimulation strategyto be carried out for a first duration. The first duration can be a fewminutes, hours or 2 to 5 days, for example. So as to implement such atemporary or permanent exclusion of individual stimulation strategies,the program prompts the processor in this variant to exclude alow-priority stimulation strategy, for a first duration, from thestimulation strategies to be carried out for an impending stimulation.

In one variant, the stimulation unit is an atrial stimulation unit, thatis, a stimulation unit that is provided and configured for stimulatingone atrium or both atria. In this variant, it is provided, inparticular, that the conductable stimulation strategies are strategiesby way of which atrial antitachycardia pacing (atrial ATP) can beapplied. In one variant, the stimulation strategy to be carried out iscardioversion, in particular by an atrial treatment.

In one variant, the system for stimulating the heart is configured totake the ventricular activity of the heart into consideration in theselection of the atrial therapy. The reason behind this is thatfundamental risks can exist for carrying out a stimulation therapy inthe atria with the presence of ventricular tachycardia (VT).Specifically, so-called retrograde conduction can occur in the case ofVT, that is, the VT is conducted back into the atrium via the cardiacstimulus conduction system and causes excitation of the atrium. Theatrial excitation caused by VT cannot be terminated by anantitachycardia pacing therapy in the atrium. The pacemaker implantshould therefore not interpret such an excitation as AT/AFib that can beterminated by atrial pacing. For this purpose, the ventricular activityhas to be measured, and also has to be taken into consideration in thedecision as to the use, type and timing of the atrial pacing therapy.For this purpose, it can be measured, for example, whether a highventricular heart rate (that is, VT) is present. Known methods foridentification by way of an ECG (intracardiac or surface ECG) can beemployed for identifying retrograde conduction. For example, 2:1retrograde conduction can be identified in a surface ECG in that P wavesare visible after every other R wave. As a result, one embodiment of thepresent system for stimulating the heart is designed to determine therisk of retrograde conduction of ventricular tachycardia for the atria,and to adapt the stimulation to be delivered such that this risk isminimized to the extent possible. For this purpose, the program promptsthe processor to initially determine a ventricular cardiac rhythm (thatis, a ventricular activity) when the detected cardiac rhythm disturbanceis atrial tachycardia. The risk of retrograde conduction of ventriculartachycardia in at least one atrium is then assessed based on thedetermined ventricular heart rhythm. A stimulation intended to treat theatrial tachycardia is then adapted as needed, in terms of time and/orlocation, taking the risk of retrograde conduction of ventriculartachycardia into consideration. Taking the ventricular activity intoconsideration in such a way can prevent atrial pacing from beingdelivered when the atrial excitation is caused by VT, and thus cannot beterminated by atrial pacing. When such a condition is identified, thesystem for stimulation according to the invention may, for example, notcarry out or delay the atrial antitachycardia pacing therapy to beapplied.

Within the scope of the assessment of the ventricular heart rhythm withrespect to the risk of retrograde conduction, discrimination features,such as the ratio of atrial to ventricular rhythm or the ventricularsignal morphology, are preferably derived and used to adapt the locationand/or time for applying the atrial antitachycardia pacing therapy. Itis possible to entirely suppress a planned atrial antitachycardia pacingtherapy when the risk of retrograde conduction of ventriculartachycardia was assessed as being too high.

In one variant, the stimulation unit is provided and configured to carryout the stimulation in the form of electrical stimulation or in the formof optical stimulation. As a result, the stimulation unit offersdifferent options for treating the previously detected cardiac rhythmdisturbance. The decision as to which physical principle is selected forthe corresponding treatment can be made, for example, by taking theseverity of the detected cardiac rhythm disturbance into consideration.

One aspect of the present invention relates to a method for controllingthe operation of an implantable system for stimulating a human heart oran animal heart. In particular, it is intended that the operation of animplantable system is controlled according to the above descriptions.This control method comprises the steps described hereafter.

First, it is checked by way of a first detection unit whether a cardiacrhythm disturbance is present in a cardiac region of a heart of a humanpatient or an animal patient.

Thereafter, a suitable stimulation strategy is selected. For thispurpose, a selection criterion that includes a measurement variable or avariable calculated from a measurement variable is used. The measurementvariable is a physiological measurement variable of the patient, apathophysiological measurement variable of the patient and/or anon-physiological measurement variable indicating a state of thepatient. A combination of different measurement variables isconceivable. Moreover, the different measurement variables can bearithmetically related to one another and, if needed, can also be givendifferent weightings.

When a suitable stimulation strategy was selected, at least one impulseis generated in a stimulation unit for stimulating the cardiac region inwhich the cardiac rhythm disturbance was detected. The type, form andduration of the at least one impulse are decided based on the selectedstimulation strategy. This strategy thus defines the pulse to begenerated, and further designs the same.

Thereafter, data regarding a success and/or an efficiency of a conductedstimulation is collected and provided for further processing. This datais then compared to a predefinable success and/or efficiency criterionwithin the scope of the control method. If the predefinable successand/or efficiency criterion was achieved, no further method step isrequired. If, in contrast, the predefinable success and/or efficiencycriterion was not achieved, the stimulation strategy is optimized. Thisoptimization is used to achieve better success and/or greater efficiencyduring a subsequent stimulation using an optimized stimulation strategy.The optimization includes a change in the stimulation strategy withrespect to at least one parameter. These parameters can be, for example,a form of the treatment, a number of the treatments, a combination ofdifferent treatments, a frequency of the treatments, and/or a point intime of the treatment. The aforementioned parameters can be usedindividually or in any arbitrary combinations with one another.

One aspect of the present invention relates to a computer programproduct including computer-readable code, which prompts a processor tocarry out the steps described hereafter when the code is being executedon the processor.

First, it is detected by way of a first detection unit whether a cardiacrhythm disturbance is present in a cardiac region of a heart of a humanpatient or an animal patient.

Thereafter, a suitable stimulation strategy is selected based on aselection criterion. The selection criterion includes a measurementvariable or a variable calculated from a measurement variable. Themeasurement variable can be a physiological measurement variable of thepatient, a pathophysiological measurement variable of the patient and/ora non-physiological measurement variable indicating a state of thepatient.

The program now prompts the processor to stimulate the cardiac region inwhich the cardiac rhythm disturbance was detected. This stimulation iscarried out by way of a stimulation unit, wherein the manner of thestimulation is defined by the selected stimulation strategy.

Afterwards, a success and/or an efficiency of the conducted stimulationare detected.

This detected success and/or this detected efficiency are then comparedto a predefinable success and/or efficiency criterion.

If the success and/or efficiency criterion—if necessary, within thescope of a likewise predefinable tolerance—was achieved, no furthermethod step is required. If, in contrast, the predefinable successand/or efficiency criterion was not achieved, the stimulation strategyis optimized. This is used to achieve better success and/or greaterefficiency during a subsequent stimulation using an optimizedstimulation strategy. The optimization includes a change in thestimulation strategy with respect to at least one parameter. Theparameter can be a form of the treatment, a number of the treatments, acombination of different treatments, a frequency of the treatments,and/or a point in time of the treatment. Arbitrary combinations andsubsets of the aforementioned parameters can be taken intoconsideration.

One aspect of the present invention relates to a method for treating ahuman patient or an animal patient in need of such treatment. Thismethod is carried out by way of an implantable system for stimulatingthe heart of the patient, wherein the system comprises a processor, amemory unit, a stimulation unit, and a first detection unit fordetecting a cardiac rhythm disturbance in a cardiac region. Thetreatment method comprises the steps described hereafter.

First, it is detected by way of the first detection unit whether acardiac rhythm disturbance is present in a cardiac region of a heart ofa human patient or an animal patient.

When such a cardiac rhythm disturbance was detected, a suitablestimulation strategy is selected based on a selection criterion. Theselection criterion includes a measurement variable or a variablecalculated from the measurement variable. The measurement variable is aphysiological measurement variable of the patient, a pathophysiologicalmeasurement variable of the patient and/or a non-physiologicalmeasurement variable indicating a state of the patient. It is possibleto provide more than one measurement variable, wherein arbitrarycombinations of the aforementioned measurement variables or ofmeasurement variables from the measurement variable groups can be used.

Afterwards, the cardiac region in which the cardiac rhythm disturbancewas detected is stimulated by way of the stimulation unit using theselected stimulation strategy.

Thereafter, a success and/or an efficiency of the conducted stimulationare detected. This can take place by way of the first detection unit ora further detection unit of the implantable system.

The detected success and/or the detected efficiency are then compared toa predefinable success and/or efficiency criterion.

If the predefinable success and/or efficiency criterion was achieved, nofurther method step is required. If, in contrast, the predefinablesuccess and/or efficiency criterion was not achieved, the stimulationstrategy is optimized, so that better success and/or greater efficiencycan be achieved during a subsequent stimulation using an optimizedstimulation strategy. The optimization includes a change in thestimulation strategy with respect to at least one parameter. Thisparameter is selected from the group consisting of a form of thetreatment, a number of the treatment, a combination of differenttreatments, a frequency of the treatments, and a point in time of thetreatment. This group can, in particular, consist of the aforementionedparameters. Arbitrary combinations and subsets of the aforementionedparameters are likewise conceivable.

One aspect of the present invention relates to an implantable system forstimulating a human heart or an animal heart, having the featuresdescribed hereafter. Such a system is intended, in particular, for thepermanent implantation in a human patient or an animal patient. When thesystem is to be implanted in an animal patient, the patient ispreferably a mammal, for example a mammal selected from the groupconsisting of rodents, horses, dogs and cats.

The system comprises a processor, a memory unit, an atrial stimulationunit, a ventricular stimulation unit, and a first detection unit. Thefirst detection unit is used to detect atrial tachycardia, that is, theatrium of the heart beating at an abnormally increased rate.

According to the invention, the system is characterized in that thememory unit includes a computer-readable program, which prompts theprocessor to carry out the steps described hereafter when the program isbeing executed on the processor.

First, it is detected by way of the first detection unit whether atrialtachycardia to be treated is present in a human heart or an animal heartof the patient in whom the implantable system was implanted. This typeof tachycardia, which can also be referred to as tachycardia requiringtreatment, is characterized in that the atrial rhythm exceeds a criticalrate and/or the resulting ventricular rhythm exceeds or drops below acritical rate and/or the atrial rhythm is classified as unstable and/orthe beats of the resulting ventricular rhythm exhibit appreciablefluctuations.

In addition to non-pathological atrial tachycardia, the term ‘atrialtachycardia requiring treatment’ also encompasses pathological atrialtachycardia, which is also known under the designation ‘atrialfibrillation.’ In one variant, the method carried out by the processorrefers only to non-pathological atrial tachycardia or only topathological atrial tachycardia.

When atrial tachycardia to be treated is present, a ventricularconditioning stimulation is carried out by way of the ventricularstimulation unit. This ventricular conditioning stimulation brings theheart into a state in which it is more receptive to subsequent atrialstimulation. The heart is thus brought very deliberately into a state inwhich it exhibits increased susceptibility toward subsequent treatments.As a consequence, the system claimed according to the invention does notwait for the heart to assume a different state by itself or by prioratrial treatments. Rather, an active change in the cardiac state isbrought about by way of a ventricular conditioning stimulation. Amultitude of conditioning stimulations that are known per se arepossible to achieve such a change in the cardiac state.

As the ventricular conditioning stimulation is being carried out and/orthereafter, atrial antitachycardia pacing is applied. The atrialstimulation unit is used for this purpose. Such atrial antitachycardiapacing is also known by the technical term ‘atrial ATP’ (theabbreviation ATP denoting antitachycardia pacing). ATP is also at timesreferred to as antitachycardia pacemaker therapy.

Since the heart, as a result of the concurrent or prior ventricularconditioning stimulation, is considerably more susceptible to theapplied atrial ATP than without ventricular conditioning stimulation,the success of the atrial ATP therapy can be enhanced. This makes itpossible for the heart of the treated patient to beat more quickly againat a normal beat, and for pathological consequences of the atrialtachycardia, such as declines in performance, dizziness and thrombusformation, to occur far less frequently.

In one variant, the atrial antitachycardia pacing is only applied whilethe ventricular conditioning stimulation is being carried out. Inanother variant, atrial antitachycardia pacing is only applied after theventricular conditioning stimulation has been carried out. In anothervariant, the atrial antitachycardia pacing is applied both as theventricular conditioning stimulation is being carried out andthereafter.

In one variant, the atrial stimulation unit is designed to apply theatrial antitachycardia pacing in the form of electrical stimulation orin the form of optical stimulation. As a result, this offers differentoptions for treating the detected atrial tachycardia. Differenttreatment variants may be selected, in particular taking into accountthe severity of the detected atrial tachycardia.

In one variant, the program prompts the processor to carry out theventricular conditioning stimulation in the form of right ventricularoverdrive pacing. During overdrive pacing, the corresponding ventricleis stimulated using a rate higher than the customary (intrinsic)ventricle rate. In this way, an increase in the rate of the ventricularrhythm can be achieved.

In another variant, the program prompts the processor to carry out theventricular conditioning stimulation in the form of left ventricularoverdrive pacing. The ventricular conditioning stimulation can thusdeliberately influence, and in particular increase, only the rate of theventricular rhythm of a single ventricle.

In another variant, it is provided that the program prompts theprocessor to stimulate both ventricles equally. In this case, theventricular conditioning stimulation is carried out in the form ofbiventricular overdrive pacing. In this way, it is possible to achieve asimultaneous increase in the rate of the intrinsic ventricular rhythm ofboth ventricles.

In one variant, the program prompts the processor to carry out theventricular conditioning stimulation in the form of biventricularoverdrive pacing, and to specify a VV time deviating from a regularstimulation. The VV time (also referred to as VV delay) indicates thetime that passes between the stimulation of the right and the leftventricle. It is also referred to as intraventricular delay. When bothventricles are stimulated at the same time, the VV delay is zero.Typically, however, it is greater than zero so as to achieve that theleft ventricle is stimulated later than the right ventricle. Selecting aVV delay deviating from a regular stimulation results in a change in thecardiac state, whereby the heart is more susceptible toward concurrentlyor subsequently applied atrial antitachycardia pacing.

In one variant, the program prompts the processor to carry out theventricular conditioning stimulation so that ventricular pauses arecompensated for. This can be achieved, for example, by an intensity ofthe ventricular conditioning stimulation and/or by setting the VV delayand/or by delivering additional ventricular stimuli and/or by settingalternative ventricular stimulation vectors (such as between the rightand left ventricular electrodes).

In one variant, the program prompts the processor to couple theventricular conditioning stimulation with a short AV delay to thedetected atrial tachycardia. A ratio of n:1 is specified in the process.Specifically, the program prompts the processor to couple theventricular conditioning stimulation with an AV delay of 10 to 110 ms todetected actions of the atrial tachycardia at a ratio of n:1, wherein ncorresponds to the number of detected actions of the atrial tachycardia,and n is 2 to 6. The AV time (also referred to as AV delay) indicatesthe time that passes between a stimulation of the right atrium and theright ventricle. It is also referred to as atrioventricular delay. Whenthis AV delay is minimized, and moreover the ventricular conditioningstimulation is adapted to the detected atrial tachycardia, aparticularly advantageous reaction of the heart thus treated to theventricular conditioning stimulation is to be expected, so thatconcurrent or subsequent atrial antitachycardia pacing can be appliedparticularly effectively.

In one variant, the program prompts the processor to carry out theventricular conditioning stimulation in a manner so as to achieve aparticular physiological objective. For example, the conditioningstimulation can be carried out in such a way that the pressure in theleft and/or right atria is lowered at least briefly. As an alternativeor in addition, the conditioning stimulation can be carried out in sucha way that the risk of mitral valve regurgitation is reduced at leastbriefly or entirely avoided. As an alternative or in addition, theconditioning stimulation can be carried out in such a way that thepreload of the heart is reduced at least briefly. As an alternative orin addition, the conditioning stimulation can be carried out in such away that the blood pressure of a patient whose heart is being stimulatedby the implantable system is lowered at least briefly. As an alternativeor in addition, the conditioning stimulation can finally be carried outin such a way that a myocardial oxygen balance is improved at leastbriefly. All of these effects—either individually or in any arbitrarycombination—achieve a change in the cardiac state, which enhances asusceptibility of the heart to concurrently or subsequently appliedatrial antitachycardia pacing.

In one variant, the implantable system comprises a second detectionunit, which is used to detect an effect of the ventricular conditioningstimulation on the atrial antitachycardia pacing. As a result of thissecond detection unit, which can also comprise parts of the firstdetection unit, it is thus possible to directly or indirectly detect thecardiac effect achieved by the ventricular conditioning stimulation. Inthis way, the overall effectiveness of the stimulation carried out bythe implantable system can be improved. The reason is that it ispossible, in this way, to obtain positive feedback about the achievedeffect with respect to the cardiac state. The second detection unit can,for example, use the same electrode that is also used by the firstdetection unit. It is thus conceivable, in principle, for the seconddetection unit to detect the effect of the ventricular conditioningstimulation in the atrium of the treated heart.

In one variant, the program prompts the processor to store a success ofthe atrial antitachycardia pacing therapy and the ventricularconditioning stimulation carried out in connection with this pacingtherapy. It is thus possible to create value pairs, which each encompassthe success of the atrial antitachycardia pacing therapy and theventricular conditioning stimulation carried out at the same time orbeforehand. It is then possible to select at least one value pair fromthe stored value pairs for a subsequent treatment of the heart. Forexample, the value pair for which the best outcome of the atrialantitachycardia pacing therapy was achieved can be selected. Similarly,for example, a value pair for which the desired success of the atrialantitachycardia pacing therapy could not be achieved, despiteventricular conditioning stimulation, can be excluded. Storing can takeplace in the memory unit of the implantable system. As an alternative,another memory unit can be provided in the implantable system, which isused to store the value pairs.

One aspect of the invention relates to a method for controlling theoperation of the implantable system for stimulating a human heart or ananimal heart. This method comprises the steps described hereafter.

First, it is detected by way of a first detection unit whether atrialtachycardia to be treated (requiring treatment) is present in a humanheart or an animal heart.

If this is the case, at least one impulse is generated for a ventricularconditioning stimulation in a ventricular stimulation unit. Instead of asingle pulse, it is also possible to select a pulse sequence includingpulses having the same amplitude or different amplitudes and a constant,increasing or decreasing rate.

Simultaneously with and/or after the generation of the at least onepulse in the ventricular stimulation unit, at least one pulse for atrialantitachycardia pacing is generated in an atrial stimulation unit. Thisat least one pulse can, for example, likewise be a pulse sequenceincluding different pulses having the same amplitude or amplitudes ofdifferent magnitudes, wherein the rate between the individual pulses canbe designed to be constant, increasing or decreasing. This method thusrelates to the generation of at least one ventricular conditioningstimulation pulse and at least one atrial stimulation pulse within theimplantable system.

One aspect of the present invention relates to a non-volatile computerprogram product including computer-readable code, which prompts aprocessor to carry out the steps described hereafter when the code isbeing executed on the processor.

First, it is detected by way of a first detection unit whether atrialtachycardia to be treated is present in a human heart or an animalheart.

When atrial tachycardia to be treated is present, a ventricularconditioning stimulation is carried out by way of a ventricularstimulation unit.

As the ventricular conditioning stimulation is being carried out and/orthereafter, atrial antitachycardia pacing is applied by way of an atrialstimulation unit.

One aspect of the present invention relates to a method for treating ahuman patient or an animal patient in need of such treatment. Thistreatment is carried out by way of an implantable system for stimulatingthe heart of the patient. The system comprises a processor, a memoryunit, an atrial stimulation unit, a ventricular stimulation unit, and afirst detection unit for detecting atrial tachycardia. The methodcomprises the steps described hereafter.

First, it is detected by way of the first detection device whetheratrial tachycardia to be treated is present in the heart.

When such atrial tachycardia requiring treatment was detected, aventricular conditioning stimulation is carried out by way of theventricular stimulation unit.

During or after the ventricular conditioning stimulation, atrialantitachycardia pacing is applied by way of the atrial stimulation unit.This method thus has a direct therapeutic effect on the treated human oranimal heart so as to treat detected atrial tachycardia, and to returnthe treated heart, and in particular the atrium of the treated heart, toa customary rhythm.

One aspect of the present invention relates to an implantable system fortreating a human heart or an animal heart, having the features describedhereafter. Such a system comprises a processor, a memory unit, atreatment unit comprising a treatment electrode, and a detection unitfor detecting cardiac events requiring treatment. According to theinvention, the system is characterized in that the memory unit includesa computer-readable program, which prompts the processor to carry outthe steps described hereafter when the program is being executed on theprocessor.

First, it is detected by way of the detection device whether a cardiacevent to be treated has occurred in the human or animal heart. Thiscardiac event can, for example, be a cardiac rhythm disturbance, such asatrial or ventricular tachycardia, or cardiac arrest.

When a cardiac event to be treated was detected, initially no treatmentof this cardiac event is carried out yet. Rather, a position of thetreatment electrode is first determined. Instead of a position of thetreatment electrode, it is also possible to determine a variablecorrelating with this position. A position of a treatment electrodeshall be understood to mean the position of a conducting section of thetreatment electrode. Such a conducting section is also referred to as anelectrode pole.

Thereafter, the position of the treatment electrode or the variablecorrelating with the position is compared to a reference variable. Acardiac treatment by way of the treatment unit and the treatmentelectrode is carried out when the position of the treatment electrode,or when the variable correlating with the position, agrees with thereference variable within a predefinable tolerance.

If the ascertained position of the treatment electrode or the variablecorrelating with the position does not agree with the reference variablewithin a predefinable tolerance, the position of the treatment electrodeis inadequate. In this case, (initially) no cardiac treatment is carriedout. The reason is that the damage from such a cardiac treatment couldbe greater than the benefit. When, for example, two electrodes arelocated too close together, or one electrode is no longer disposed inthe atrium, but in the ventricle of a heart, carrying out a cardiactreatment could result in undesirable side effects, some of which areserious, which are to be avoided.

The reference variable, including the tolerance thereof, is determinedso that a position of the treatment electrode is considered to beinadequate when treatment success is unlikely due to such a position,applying the treatment could result in side effects with (potentiallynot foreseeable) consequences, or when delivering the treatment couldhave damaging consequences for the treated heart.

In any case, the actually required cardiac treatment is refrained frombeing carried out until a decision has been made as to whether atreatment should nonetheless be carried out, despite the position of thetreatment electrode having been established to be inadequate. The reasonis that, even when a position of the treatment electrode was ascertainedto be inadequate, at times the benefit of a cardiac treatment that isnonetheless carried out could be greater than any anticipated damage. Inone variant, the option of a manual or automated intervention in theprogram executed by the processor is thus provided so as to still enablecardiac treatment, even when the established position of the treatmentelectrode initially does not support such a treatment. When consideringa severity of the detected cardiac event to be treated, and thedeviation of the position of the treatment electrode from the referencevariable, however, it may be useful or necessary for saving the life ofa patient to carry out a treatment even if success of the therapy isquestionable or if (serious) side effects are feared.

The system is suitable for temporary or permanent implantation, wherein,in particular, a permanent implantation of the system in a human patientor an animal patient is intended. When the system is to be implanted inan animal patient, the patient is, in particular, a mammal, for examplea mammal selected from the group consisting of rodents, horses, dogs andcats.

The treatment unit and the treatment electrode, which can also bereferred to as the therapy unit and the therapy electrode, can be a unitand an electrode suitable for any type of treatment of a human heart oran animal heart. For example, the treatment electrode can be astimulation electrode used to stimulate human or animal heart tissue.The treatment electrode can also be a defibrillation electrode. Theexact configuration of the treatment electrode is not of particularsignificance for the presently claimed invention.

In one variant, the implantable system comprises more than one treatmentunit and more than one treatment electrode. In particular, it isprovided that one treatment electrode is provided for each cardiacregion to be treated. Multiple treatment electrodes can be connected toa single treatment unit. Typically, however, exactly one treatment unitis assigned to each treatment electrode.

In an alternative embodiment, the implantable system comprises more thanone detection unit. Again, one detection unit can be provided for eachcardiac region to be treated. The different cardiac regions to betreated can be, for example, the left atrium, the left ventricle, theright atrium or the right ventricle of a human heart or an animal heart.

In one variant, the position of the treatment electrode to be determinedis a relative position of the treatment electrode with respect to areference point of the system. This reference point can be anothertreatment electrode of the system, for example. The reference point canalso be a reference electrode of the system. For example, a portion ofthe housing of the implantable system can be configured in the form of areference electrode.

In one variant, the relative position of the treatment electrode or thevariable correlating with this relative position is determined bydetermining a distance between the treatment electrode and the referencepoint. This distance is then compared to a reference distance, whichserves as a reference variable. Such a distance determination makes itpossible to ascertain whether a relative displacement of the consideredelectrodes has taken place. It is possible to determine a singledistance between the treatment electrode and the reference point, or twoor more distances between different treatment electrodes and/or betweenone or more treatment electrodes and a reference electrode. It ispossible to apply differing weightings to the individual distances whencalculating a variable correlating with the distance. In this way, it ispossible to assign a higher weighting to a relative change in positionof an electrode in the case of which a change in position can haveparticularly serious consequences for a successful treatment, than to arelative change in position of an electrode in the case of which achange in position can have a less serious effect on a successfultreatment.

In principle, different options exist for ascertaining the absolute orrelative position of the treatment electrode. In one variant, theprogram prompts the processor to determine the relative position of thetreatment electrode by measuring an electrical current and/or bymeasuring a voltage between the treatment electrode and the referencepoint. When, for example, the distance between different treatmentelectrodes or between a treatment electrode and a reference electrode isto be determined, a voltage is applied between these electrodes. One ofthe electrodes serves as a current sink in the process. Respectiveelectrode pairs are then selected from two of the considered nelectrodes, and the voltage present between these electrodes isdetermined. When the implantable system comprises a total of nelectrodes (treatment electrodes and reference electrodes), this resultsin

$\frac{n!}{{( {n - 2} )!}{2!}} = \begin{pmatrix}n \\2\end{pmatrix}$

electrode combinations that can be used for a corresponding voltagedetermination. For example, if there are n=4 electrodes,

$\begin{pmatrix}4 \\2\end{pmatrix} = {\frac{4*3*2*1}{2*1*2*1} = 6}$

combinations result for a selection of two electrodes.

It is provided in one embodiment of the invention to apply voltagesbetween at least two to no more than n−1 electrode poles. Thereafter,the voltage between electrode poles is measured, of which at least onepole is not involved in the generation of the voltage.

Furthermore, according to another embodiment of the invention, anelectrical current is feed between at least two to no more than n−1electrode poles. At least one electrode pole serves as a current sink inthe process. Thereafter, the voltage or the current between at least twoof the n electrode poles is measured.

According to a preferred exemplary embodiment of the invention, theelectrical current and/or the voltage are delivered by way of at leastone treatment electrode and measured by way of at least one treatmentelectrode and/or reference electrode. The measurement is carried outimmediately after the delivery of the electrical current and/or thevoltage, so that an effect generated by the fed current/the appliedvoltage can be measured directly. The effect can be a physiologicaleffect generated by the current/the voltage.

In one variant, the reference point or the reference electrode issituated in the area of the thorax of the patient. As was alreadydescribed, a portion of the housing of the implantable system can serveas the reference electrode. The distance between the electrodes situatedin the heart and the reference electrode is then comparatively large.

In one variant, the voltage applied to the electrodes has a frequency ina range of 0 to 1 MHz, in particular 0.1 to 0.9 MHz, in particular 0.2to 0.8 MHz, in particular 0.3 to 0.7 MHz, in particular 0.4 to 0.6 MHz,and in particular 0.5 to 1 MHz.

In one variant, the voltage applied to the electrodes is a pulsedvoltage having a pulse duration in a range of 10 μs to 100 ms, inparticular 100 μs to 10 ms, in particular 500 μs to 5 ms, in particular750 μs to 2.5 ms, in particular 900 μs to 2 ms, and in particular 1 msto 1.5 ms.

In one variant, the intervals between the individual pulses can cover avery wide range, in terms of time. For example, it is possible toconsecutively emit a plurality of pulses in very short succession fordetermining the position of the treatment electrode, so as to then havea longer pause until the next position determination. In one variant,the times that pass between individual pulses can thus be 10 μs to 2years, in particular 50 μs to 1.9 years, in particular 100 μs to 1.8years, in particular 1 ms to 1.7 years, in particular 500 ms to 1.6years, in particular 1 second to 1.5 years, in particular 10 seconds to1.4 years, in particular 1 minute to 1.3 years, in particular 10 minutesto 1.2 years, in particular 1 hour to 1 year, in particular 1 day to 0.5years, in particular 1 week to 0.25 years, and in particular 2 weeks to1 month. It is also conceivable that the pulse spacing during individualmeasurements is in an interval made up of the shorter time periods (forexample 10 μs to 1 second) and the spacing between pulses of differentmeasurements is in an interval made up of the longer segments (forexample 1 minute to 2 years). Of course, all of the intervals explicitlymentioned above or the intervals to be formed otherwise of the upper andlower values delimiting these intervals can be used for the duration ofthe pulse spacing.

In one embodiment, a measurement comprises a plurality of individualmeasuring pulses, which are emitted in the form of so-called bursts.

In one variant, at least one measurement is carried out per year, so asto enable continuous position monitoring of the treatment electrode.

In one variant, the measurement of the voltage applied to the electrodesor of the currents introduced into the electrodes is carried out in theform of an impedance measurement. For example, 2-pole, 3-pole and/or4-pole impedance measuring methods can be employed for this purpose.

In one variant, the current fed into the electrodes or the voltageapplied to the electrodes can be measured directly by way of theelectric fields generated in the body of the patient. In an alternativeembodiment, moreover an indirect measurement is also contemplated. Thereason is that the applied voltage or the fed current causes excitationof a cardiac region in which one of the electrodes involved in themeasurement is positioned, which subsequently spreads to another cardiacregion. This results in a physiological delay of the excitationpropagation. Based on the pattern of the excitation propagation and/orthe physiological delay of the excitation propagation, it is possible todetermine the effect of the fed current or of the applied voltage.

The current or the voltage generates electric fields that cause aparticular effect in the body. This effect and/or the effect determinedindirectly via the delayed physiological effect of the current or thevoltage represents a characteristic parameter for the position of thetreatment electrode, and in particular for the distance between thetreatment electrode and a reference point, such as a referenceelectrode. This parameter is a variable correlating with the positionwithin the meaning of the present invention.

In an alternative embodiment, it is also contemplated to measure both animmediate (direct) effect of the fed current or of the applied voltageand a delayed physiological effect of the current or the voltage and touse this for determining the position of the treatment electrode.

In an alternative, the processor is prompted by the program to assessthe detected delayed physiological effect. In particular, it is providedto carry out a plausibility check so as to check whether the reason forthe detected physiological delay is the assumed position of thetreatment electrode. Limiting values can be predefined for thisplausibility check, which have to be adhered to within a likewisepredefinable tolerance range. If an excessively large delayedphysiological effect or an excessively small delayed physiologicaleffect is detected, this plausibility check may cause the obtainedresult not to be considered to be outside the range to be adhered tofrom the outset. Rather, this may be an indication that the measurementis faulty and has to be repeated. In contrast, there are many reasonsthat support the assumption that the measured position of the treatmentelectrode corresponds to the actual position thereof, in particular whenonly minor deviations from the presumed position are established duringthe plausibility check. It is then possible to ascertain in a subsequentstep whether this position in fact agrees with the reference variablefor this position within the predefinable tolerance.

Whenever a predefinable value is described or explained within the scopeof the present application, this value can be fixedly predefined orfreely programmable, for example. In such a case, it is also possiblefor a corresponding value to be selected from a plurality of exemplaryvalues. These exemplary values can be predefined in ranges meaningfulfor the particular application and, for example, can be made availablefor selection in what experience has shown to be realistic intervals.

In one variant, it is ascertained based on a direct effect of theelectric fields generated in the body whether a permitted minimumdistance between two electrodes is adhered to or not met. For example,it is possible to check that a measurement signal ascertained as aresult of an applied voltage or a fed current does not exceed athreshold value serving as the reference variable. If the thresholdvalue is not exceeded, the minimum distance is adhered to.

In one variant, the sensitivity of the ascertainment of a distancebetween two electrodes can be increased by combining differentmeasurement methods with one another. For example, when theascertainment of the immediate effect of the applied voltage or of thefed current has already yielded the result that a drop below the minimumdistance did not occur, it can additionally be checked that thephysiologically delayed effect achieved by the applied voltage or thefed current does not drop below a predefinable delay period. If a dropbelow the defined delay period does not occur, two confirmationsobtained by different measurement methods exist that a drop below theminimum distance between the electrodes did not occur.

In one variant, it is provided that the position of the treatmentelectrode is an absolute position of the treatment electrode within ahuman heart or an animal heart when the system is implanted in a humanor an animal. This means that the position, in this case, is determinedindependently of other components of the then implanted system. Theexpression “absolute position” denotes the arrangement of the treatmentelectrode in the heart or in a particular cardiac region.

So as to make such an absolute position determination of the treatmentelectrode possible, the treatment electrode comprises an accelerationsensor in one variant. Such an acceleration sensor, which can beconfigured, for example, as a linear acceleration sensor or a rotationrate sensor or gyroscope, can be used to track a movement of thetreatment electrode within the heart.

In one variant, it is provided for this purpose that the program promptsthe processor to create an acceleration profile of the treatmentelectrode by way of acceleration data collected by the accelerationsensor. Moreover, the processor is prompted to correlate thisacceleration profile with the cardiac rhythm of the human or animalheart in which the corresponding treatment electrode is situated. Inthis way, it is possible to ascertain whether the treatment electrode istracking the movements of the cardiac region in which the treatmentelectrode is situated or presumed. If the acceleration profile of aventricular treatment electrode is synchronous with the ventricularcardiac rhythm of the corresponding ventricle, the treatment electrodeis still situated in the ventricle in which it was originally disposed.If, in contrast, a correlation of the acceleration profile of thetreatment electrode and the cardiac rhythm of a particular cardiacregion shows that the treatment electrode is tracking the movements of acardiac region in which it is not supposed to be situated (for example,an atrial treatment electrode tracks a ventricular cardiac rhythm), thisdemonstrates that the treatment electrode is no longer situated in thecardiac region in which it was originally disposed. This means that adislocation of the treatment electrode has taken place, which regularlyprecludes this treatment electrode from being activated for carrying outa cardiac therapy. The reason is that the expected therapy success wouldthen not materialize. Rather, (serious) side effects of a correspondingcardiac treatment would have to be expected. A relocation of thetreatment electrode would have to be carried out first here, so that thedesired treatment success can in fact be achieved.

In one variant, data is also collected by sensors that are situatedoutside the human or animal heart and that are not influenced by themovements of the heart, during the determination of the absoluteposition of the treatment electrode. By including such supplementalsensor data, it is possible to reduce, or even eliminate, artefacts thatmay occur elsewhere. This increases the accuracy of the determination ofthe absolute position of the treatment electrode.

In one variant, the system comprises a patient state sensor. Such apatient state sensor is used to determine a body position or an activitystate of a patient in whom the system was implanted. Such a patientstate sensor may be a position sensor, for example, which can be used toascertain whether the patient is in an upright position or a horizontalposition. For example, a sensor that can be used to monitor the heartrate of the patient is a patient state sensor suitable for determiningthe activity state of the patient. The heart rate is typically monitoreddirectly by one or more electrodes of the system for treating the heart,so that the sensors already present in the system can assume thefunction of the patient state sensor, which is why a separate patientstate sensor is not necessarily required in such a case. Detecting thebody position or the activity state of the patient makes it possible tocollect additional data, which increases the reliability of theremaining measurement data since it can provide an explanation forpotentially abnormal measurement data.

In one variant, the program prompts the processor to store a progressionof the position of the treatment electrode over time. In this way, it ispossible to establish a trend of the position of the treatmentelectrode. For example, an onsetting dislocation of the treatmentelectrode can thus be identified at an early stage, when a change in theposition of the treatment electrode that, per se, is still within thepredefined tolerance range is found, and, at the same time, it isevident that this change in position is taking place in exactly onedirection (for example, an increasing distance or a decreasingdistance). Such an analysis of the progression of the position of thetreatment electrode can also be used to ascertain the positionalstability of the treatment electrode. In this way, for example, animminent loose connection of the treatment electrode can be identifiedat an early stage.

In one variant, the program prompts the processor to store only thosevalues of the position of the treatment electrode which were collectedwhen the patient was in a defined body position and/or in a definedactivity state. The data collected by the optionally provided patientstate sensor is preferably used for this purpose. By limiting the valuesof the position of the treatment electrode to be stored, an overall morereliable trend of a change in the position of the treatment electrodecan be ascertained. The reason is that overall improved comparability ofthe stored values is achieved when the measurements that were obtainedfor assessing the position of the treatment electrode are only storedwhen they relate to a comparable body position of the patient or acomparable activity state of the patient. It is then possible to providemore precise information as to the positional stability of the treatmentelectrode. In this way, artefacts are minimized or eliminated.

In one variant, the program prompts the processor to carry out aposition determination of the treatment electrode even when no cardiactreatment of the corresponding human or animal heart is to be carriedout. In this way, it is possible to collect measurement dataindependently of a cardiac treatment, which provides insights into theposition of the treatment electrode. When such data is collected atregular or irregular intervals, information as to the positionalstability of the treatment electrode can be provided. An (onsetting)dislocation of the treatment electrode can thus be identified at anearly stage, which may then possibly be corrected even before the needto carry out a cardiac treatment.

In one variant, the program prompts the processor to carry out a cardiactreatment after a presettable time has elapsed or in response to asignal if a cardiac event to be treated was established beforehand. Thiscardiac treatment takes place in such a case by way of the treatmentunit and the treatment electrode, regardless of the previouslyascertained position of the treatment electrode. This means that thissafety step makes a cardiac treatment possible even if an inadequateposition of the treatment electrode was ascertained. The reason is that,at times, the established deviation of the position of the treatmentelectrode from the expected position is comparatively small, while thecardiac event to be treated is comparatively serious. Taking thepatient's interest into consideration, it may be more advantageous on anoverall basis to carry out a cardiac treatment, and accept side effects,than to suppress such a cardiac treatment.

An external input signal generated by a physician can, for example, be asignal that prompts the processor to carry out a cardiac treatment,regardless of the ascertained position of the treatment electrode. As aresult, a physician—taking the patient's interest and the medical riskof a cardiac treatment into consideration—has the option to carry out acardiac treatment, despite a seemingly or effectively dislocatedtreatment electrode.

In one variant, the system comprises at least one device for emittingand/or receiving acoustic waves. This device is used to determine theposition of the treatment electrode. The acoustic waves can beultrasonic waves, for example. An emitter for acoustic waves can bedisposed on the treatment electrode, for example. A receiver for theacoustic waves emitted by the emitter can be disposed on the referencepoint. By way of signal attenuation, taking place after the acousticwaves have been emitted, and/or a phase shift compared to the fedacoustic signal, it is then possible to obtain additional informationabout the distance between the treatment electrode and the referencepoint. The delay that results from the acoustic signal propagation inthe heart or in the body of the patient is orders of magnitude shorterthan a physiological delay of the excitation propagation caused by theintroduction of a current pulse into the heart. By a combined evaluationof the immediate effect of a fed current or an applied voltage by way ofthe electric fields generated thereby in the heart and/or the delayedphysiological excitation as a result of the applied voltage or the fedcurrent and/or the emitted and received acoustic signals, it is thuspossible to work in up to three different levels of time, which allows avery precise position determination of the treatment electrode.

It is also possible to dispose the emitter of the acoustic waves oracoustic signals on the reference point, instead of on the electrode,and to dispose the receiver on the electrode. At the same time, it ispossible to use a transceiver for acoustic signals instead of a receiverthat is separate from the emitter. It is also possible to provide theemitter, the receiver or the transceiver on a different component of theimplantable system, instead of on the electrode. In such a case, it isuseful to provide a reflective element on the electrode, which reflectsthe acoustic signals directed at the electrode. In such a case, it ispossible to collect relevant data for the determination of the distancebetween the electrode and the emitter, the receiver or the transceiverfrom the progression of the acoustic signals toward the electrode and/oraway from the electrode.

In one variant, the system comprises at least one device for emittingand/or receiving electromagnetic waves. This embodiment of the device isused to determine the position of the treatment electrode distancemeasurement using electromagnetic waves. The electromagnetic waves canhave a frequency in the range of 1 MHz to 1 GHz, in particular of 10 MHzto 900 GHz, in particular of 100 MHz to 800 GHz, in particular of 500MHz to 700 GHz, in particular of 1 GHz to 600 GHz, in particular of 10GHz to 500 GHz, in particular of 100 GHz to 400 GHz, and in particularof 200 GHz to 300 GHz. The electromagnetic waves are galvanically fedinto the tissue.

In one variant, the electromagnetic waves are fed into the cardiactissue in the frequency range of 300 MHz to the infrared range, that is,300 GHz. Thereafter, it is possible to ascertain a distance between thetreatment electrode and the reference point based on a transmissionmeasurement of the electromagnetic waves. According to an exemplaryembodiment of the present invention, it is possible to useelectromagnetic waves in the visible frequency range instead of acousticwaves. Suitable frequency ranges are between 400 THz and 800 THz, inparticular between 500 THz and 700 THz, and in particular between 550THz and 650 THz. Emitters and receivers or transceivers can also be usedin the case of electromagnetic waves. It is possible, but not mandatory,to arrange an emitter, a receiver or a transceiver on the electrode. Itis likewise possible to use reflective elements, which reflect theelectromagnetic waves, but this is only useful for certain frequencyranges. The reason is that, in particular, light in the visible rangepenetrates only short distances in the human tissue, so that theluminous intensity may potentially already be too low once a reflectiveelement is reached. Lower-frequency electromagnetic waves, however, havea larger range in human tissue, so that reflections are possible here.Instead of simple transmission measurements, combined reflection andtransmission measurements are also possible.

In one variant, the cardiac event to be detected which is to be treatedby way of the implantable system is atrial tachycardia. In such a case,the cardiac treatment is atrial antitachycardia pacing. The treatmentelectrode may also be referred to as a stimulation electrode in thiscase.

One aspect of the present invention relates to a method for controllingthe operation of an implantable system for treating a human heart or ananimal heart, and in particular to an implantable system according tothe above description. This method comprises the steps describedhereafter.

First, it is detected by way of a detection unit whether a cardiac eventto be treated has occurred in a human heart or an animal heart.

If a cardiac event to be treated has occurred, a position of a treatmentelectrode is determined. As an alternative or in addition, a variablecorrelating with this position of the treatment electrode can bedetermined.

Subsequently, the position of the treatment electrode or the variablecorrelating with the position is compared to a reference variable.

When the position of the treatment electrode or the variable correlatingwith the position agrees with the reference variable within apredefinable tolerance, an impulse for a cardiac treatment is generatedin a treatment unit of the system. This impulse can then be forwardedvia a treatment electrode.

If, in contrast, the position of the treatment electrode or the variableof the treatment electrode correlating with the position does not agreewith the reference variable within a predefinable tolerance, no impulsefor a subsequent cardiac treatment is generated in the treatment unit.

One aspect of the present invention relates to a non-volatile computerprogram product including computer-readable code, which prompts aprocessor to carry out the steps described hereafter when the code isbeing executed on the processor.

First, it is detected by way of a detection device whether a cardiacevent to be treated has occurred in the human or animal heart.

When a cardiac event to be treated was detected, initially no treatmentof this cardiac event is carried out yet. Rather, a position of atreatment electrode is first determined. Instead of a position of thetreatment electrode, it is also possible to determine a variablecorrelating with this position.

Thereafter, the position of the treatment electrode or the variablecorrelating with the position is compared to a reference variable. Acardiac treatment by way of the treatment unit to which the treatmentelectrode is assigned is carried out when the position of the treatmentelectrode, or when the variable correlating with the position, agreeswith the reference variable within a predefinable tolerance.

If the ascertained position of the treatment electrode or the variablecorrelating with the position does not agree with the reference variablewithin a predefinable tolerance, the position of the treatment electrodeis inadequate. In this case, (initially) no cardiac treatment is carriedout. The reason is that the damage from such a cardiac treatment couldbe greater than the benefit.

A further aspect of the present invention relates to a method fortreating a human patient or an animal patient requiring such treatment,by way of an implantable system for treating a human heart or an animalheart, wherein the system comprises a processor, a memory unit, atreatment unit comprising a treatment electrode, and a detection unitfor detecting a cardiac event requiring treatment. The method comprisesthe steps described hereafter.

First, it is detected by way of the detection unit whether a cardiacevent to be treated has occurred in the heart of the patient.

If a cardiac event to be treated has occurred, a position of thetreatment electrode or a variable correlating with this position isdetermined.

The position of the treatment electrode or the variable correlating withthe position is then compared to a reference variable.

When the position of the treatment electrode or the variable correlatingwith the position agrees with the reference variable within apredefinable tolerance, a cardiac treatment is carried out by way of thetreatment unit and the treatment electrode.

In contrast, when the position of the treatment electrode or thevariable correlating with the position does not agree with the referencevariable within a predefinable tolerance, initially no cardiac treatmentis carried out by way of the treatment unit and the treatment electrode.

One aspect of the present invention relates to an implantable system forthe diagnostic and/or therapeutic treatment of a human patient or ananimal patient, having the features described hereafter. Such a systemcomprises a processor, a memory unit, a treatment unit, and a remotedata transmission unit. The treatment unit is used to carry out adiagnostic and/or therapeutic treatment of the patient in whom thesystem was implanted. By way of the remote data transmission unit, datacan be transmitted to a receiver located remotely in relation of theimplantable system via remote data transmission networks, which areknown per se, such as WLAN or mobile radio communication, and inparticular wirelessly.

According to the invention, it is provided that the memory unitcomprises a computer-readable program, which prompts the processor tocarry out the steps described hereafter when the program is beingexecuted on the processor.

Initially, it is ascertained whether a treatment functionality of thetreatment unit could jeopardize a patient in whom the system wasimplanted if a diagnostic and/or therapeutic treatment of the patientwhich corresponds to the treatment functionality were to be carried outby way of the treatment unit. It is thus ascertained in advance whethersuch a patient risk could exist with a planned (but not yetadministered) treatment.

When such a possible patient risk was ascertained, the correspondingtreatment functionality is deactivated. The treatment unit typicallyincludes a plurality of different treatment functionalities. Typically,each of these treatment functionalities can be deactivated independentlyof other treatment functionalities. It is also possible to jointlydeactivate certain treatment functionalities that form a group.

As a result of the deactivation, a therapeutic or diagnostic treatmentof the patient defined by the treatment functionality can no longer becarried out by the treatment unit. This is not possible again until thetreatment functionality was reactivated. As was already mentioned at theoutset, the approaches known from the prior art require a patient to seea specialist to have the treatment functionality reactivated.

According to the presently claimed invention, however, a step ofreceiving reactivation data now takes place by way of the remote datatransmission unit. It is thus possible by way of the presently claimedinvention to send reactivation data to the implantable system via theremote data transmission unit.

The deactivated treatment functionality is then reactivated based on thereceived reactivation data. If different treatment functionalities werepreviously deactivated, the reactivation data can include information asto which of the deactivated treatment functionalities are to bereactivated. It is also possible to always reactivate all previouslydeactivated treatment functionalities by way of the receivedreactivation data.

As a result of a reactivation of the treatment functionality, adiagnostic and/or therapeutic treatment corresponding to the treatmentfunctionality can subsequently be carried out again.

It is provided that the reactivation data can only be transmitted to theimplantable system by trained medical staff, in particular physicians,specialized in such implantable systems. It is then possible to ensurethat the treatment functionality is only reactivated if a risk for thepatient is no longer presumed to exist. At the same time, however, it isnot necessary for the patient to see the corresponding physician ortrained medical staff. This avoids needless travel for the patient, andsaves the physician from having unnecessary patient visits.

In one variant, the program prompts the processor to send status data byway of the remote data transmission unit. This status data indicateswhether a particular treatment functionality of the treatment unit isactivated or deactivated. This status data can then be received by aremotely situated computer (for example, at a physician specializing inimplants). The physician or another user of the remotely situatedcomputer is then able to identify which treatment functionalities of theimplantable system were deactivated, so as to decide whether areactivation of these treatment functionalities is in the interest ofthe patient. The status data—as well as the reactivation data in this orin other exemplary embodiments—can be transmitted in encrypted form. Thesufficiently known, conventional encryption mechanisms are suitable forthis purpose.

In one variant, it is possible to permit individual treatmentfunctionalities to be reactivated, while disallowing a reactivation ofother treatment functionalities. For this purpose, one or more treatmentfunctionalities can be assigned to a first group, and one or more othertreatment functionalities can be assigned to a second group. The twogroups can subsequently be treated differently with respect to thereactivation. Specifically, the program prompts the processor in thisvariant to permit a reactivation of one or more treatmentfunctionalities assigned to the first group, based on the receivedreactivation data. At the same time, the program prompts the processorto disallow a reactivation of individual or multiple treatmentfunctionalities assigned to the second group. Providing different groupsthus enhances the patient's safety since certain treatmentfunctionalities that pose a particularly high risk for the patient canthus be precluded in a targeted manner from being reactivated by way ofremote data transmission. So as to reactivate such functions, it isstill necessary to see a physician specialized in implantable systems,who is then able to carry out a corresponding reactivation after havingexamined the patient.

So as to assign individual or multiple treatment functionalities to thefirst group or to the second group, the processor uses assignment datain one variant. This assignment data can be stored in the memory unit ofthe implantable system or be transmitted to the system by other means.Such assignment data makes it possible to flexibly assign treatmentfunctionalities to the first group or to the second group. For example,such assignment data can provide that a particular treatmentfunctionality is to be assigned to the first group at a first point intime. At a later point in time, such assignment data can prompt anassignment of the same treatment functionality to the second group. Theassignment data can, for example, take a state of health of the patientinto consideration which affords or necessitates a facilitated or moredifficult reactivation of particular treatment functionalities.

In one variant, assignment data is precluded from being transmitted tothe implantable system by way of the remote data transmission device.

In one variant, the system comprises a near field telemetry unit. Inthis variant, the program prompts the processor to receive assignmentdata by way of the near field telemetry unit. In this way, it ispossible to clear certain treatment functionalities for reactivation, orto exclude these from reactivation, and more particularly, for example,when the patient is visiting a physician not specialized in implants,such as his or her primary care physician. The primary care physician isthen not able to directly initiate a reactivation of individualpreviously deactivated treatment functionalities. However, it ispossible for the primary care physician to clear certain treatmentfunctionalities by way of the near field telemetry unit. Subsequently,reactivation data can then be transmitted by a specialist to theimplantable system and received by the same by way of the remote datatransmission unit. In this way, access to the implantable system wouldbe subject to dual control. On the one hand, certain treatmentfunctionalities have to be cleared for reactivation by way of the nearfield telemetry unit. On the other hand, a physician specialized inimplants or accordingly trained medical staff additionally has to sendreactivation data to the implantable system. Such a multi-stage safetyprocedure makes it possible to significantly reduce a risk due tounauthorized access to the implantable system. Nonetheless, the patienthas to see only one physician, who moreover does not need to be aspecialist for implants.

The assignment data transmitted to the implantable system by way of thenear field telemetry unit or by other means can, for example, allow atemporary assignment of certain treatment functionalities to the firstgroup of treatment functionalities. It may then be possible, forexample, to permit a reactivation of the previously deactivatedtreatment functionality within a time window having a duration of, forexample, 1 minute to 10 hours, in particular 5 minutes to 5 hours, inparticular 10 minutes to 2 hours, in particular 20 minutes to 1.5 hours,and in particular 30 minutes to 1 hour. Subsequently, the correspondingtreatment functionality is automatically assigned to the second group. Areactivation of the treatment functionality is then no longer possible.If no reactivation has taken place within the time window, initially newassignment data has to be transmitted to the implantable system so as toreopen the fundamental option of reactivating the deactivated treatmentfunctionality.

In one variant, the implantable system is a system for treating, and inparticular for stimulating, a human hear or an animal heart. Forexample, the system can be a cardiac pacemaker, which has differentfunctionalities. The system can, for example, be an implantable systemfor stimulating a human heart or an animal heart, which is provided andconfigured to apply atrial antitachycardia pacing. However, arbitraryother functionalities are also conceivable.

In one variant, the system can also be a medical product, which is usedfor entirely different diagnostic and/or therapeutic applications withina patient. Examples include implantable defibrillators,neurostimulators, implantable medical pumps and ventricular assistdevices.

In one variant, the treatment unit includes at least one treatmentfunctionality, which is selected from the group consisting ofventricular pacing, ventricular conditioning stimulation, atrial pacing,atrial antitachycardia pacing and defibrillation. Ventricular pacingmay, for example, be right ventricular overdrive pacing, leftventricular overdrive pacing, or biventricular overdrive pacing.Biventricular overdrive pacing can be carried out, for example, with aVV delay deviating from a regular stimulation. Specific adaptations ofthe ventricular conditioning stimulation to previously detected atrialtachycardia, as they are described elsewhere in the present application,are likewise conceivable.

One aspect of the present invention relates to a treatment systemcomprising an implantable system for the diagnostic and/or therapeutictreatment of a human patient or an animal patient according to the abovedescriptions, and a remote access unit disposed remotely therefrom. Asdescribed, the implantable system comprises a first processor, a firstmemory unit, a treatment unit, and a first remote data transmissionunit. The remote access unit comprises a second processor, a secondmemory unit, and a second remote data transmission unit. The remoteaccess unit can be a conventional computer. The first memory unitincludes a first computer-readable program, which prompts the firstprocessor to carry out the steps described hereafter when the program isbeing executed on the first processor.

Initially, it is ascertained whether a treatment functionality of thetreatment unit could jeopardize a patient in whom the system wasimplanted if a diagnostic and/or therapeutic treatment of the patientwhich is specified by the treatment functionality were to be carriedout.

When such a potential patient risk was ascertained, the treatmentfunctionality is deactivated. The treatment defined by the treatmentfunctionality can then no longer be carried out.

If thereafter reactivation data is received by way of the first remotedata transmission unit, the deactivated treatment functionality maysubsequently be reactivated, taking the received reactivation data intoconsideration.

The second memory unit includes a second computer-readable program,which prompts the second processor to carry out the steps describedhereafter when the program is being executed on the processor.

Reactivation data is generated in response to an input or a programrequest. This reactivation data is then transmitted by way of the secondremote data transmission unit. The steps of generating the reactivationdata and of transmitting the reactivation data are typically carried outprior to the step of receiving the reactivation data by way of the firstremote data transmission unit. It is possible in the process andcontemplated that the reactivation data has already been generated andis only transmitted by way of the second remote data transmission unitwhen a reactivation of a particular treatment functionality becomesnecessary, so that the data can be received by way of the first datatransmission unit.

An input that prompts the generation of reactivation data can, forexample, be a user input on the remote access unit. For example, afterhaving been informed that a particular implantable system hasdeactivated a treatment functionality, which is now to be reactivated, aphysician is able to prompt a generation of reactivation data by aninput on a user interface. For this purpose, the physician canpreviously obtain assurance, by telephone or other means, that areactivation of the treatment functionality no longer poses a risk forthe patient, for example because the condition of the patient has sincechanged.

In one variant, the second program prompts the second processor toreceive status data of the implantable system prior to the generation ofthe reactivation data by way of the second remote data transmissionunit. This status data indicates whether a particular treatmentfunctionality of the treatment unit is activated or deactivated. Thereason is that reactivation data with respect to a treatmentfunctionality only has to be transmitted when this treatmentfunctionality has in fact been deactivated. The status data can alsoindicate whether or not a remote reactivation of the respectivetreatment functionality is permissible.

For example, it is possible that a physician tasked with thereactivation of a treatment functionality first checks the status of thecorresponding implantable system. This can take place based on suchstatus data, which is transmitted from the first remote datatransmission unit to the second remote data transmission unit. When thephysician then recognizes that a particular treatment functionality wasdeactivated, but he or she also has information that a risk to thepatient no longer exists as a result of a change in the patient'scondition that has since taken place, the physician is able to generatethe required reactivation data in the remote access unit. Such a changein the patient's condition may have occurred, for example, as a resultof a treatment with pharmaceuticals.

In one variant, it is provided that the fundamental option ofreactivating a treatment functionality cannot be altered remotely. Whena treatment functionality is thus labeled to the effect that it is notreactivatable remotely, it is not possible for a physician to implementa change to this labeling by way of remote access to the effect that areactivation by way of remote access is made possible after all. Rather,in one variant, an interaction with the implantable system in muchgreater proximity, for example through direct access or access by way ofa near field telemetry unit, is required for this purpose. In this way,unauthorized access to the implantable system and the activity status ofthe individual treatment functionalities is made significantly moredifficult.

One aspect of the present invention relates to a method for controllingthe operation of an implantable system for the diagnostic and/ortherapeutic treatment of a human patient or an animal patient accordingto the above descriptions. This method comprises the steps describedhereafter.

Initially, it is ascertained whether a treatment functionality of atreatment unit of the system could jeopardize a patient in whom thesystem was implanted if a diagnostic and/or therapeutic treatment of thepatient defined by the treatment functionality were to be carried out.

When such a possible patient risk is identified, the treatmentfunctionality is deactivated.

Only after reactivation data has been received by way of a remote datatransmission unit can the deactivated treatment functionality bereactivated, based on the received reactivation data. If, in contrast,such reactivation data is not received, the treatment functionalityremains in the deactivated state thereof.

One aspect of the present invention relates to a computer programproduct including computer-readable code, which prompts a processor tocarry out the steps described hereafter when the code is being executedon the processor.

Initially, it is ascertained whether a treatment functionality of atreatment unit of an implanted system for the diagnostic and/ortherapeutic treatment of a human patient or an animal patient couldjeopardize a patient in whom the system was implanted if a diagnosticand/or therapeutic treatment of the patient defined by the treatmentfunctionality were to be carried out.

When such a potential patient risk was ascertained, the treatmentfunctionality is deactivated.

A reactivation of the treatment functionality is only possible whenreactivation data is available. This reactivation data is received byway of a remote data transmission unit. After having been received, thereactivation data can be used to reactivate the previously deactivatedtreatment functionality. If no reactivation data is received, thetreatment functionality remains in the deactivated state thereof.

One aspect of the present invention relates to a method for treating ahuman patient or an animal patient in need of such treatment. Thistreatment is carried out by way of an implantable system for thediagnostic and/or therapeutic treatment. The system comprises aprocessor, a memory unit, a treatment unit, and a remote datatransmission unit. The method comprises the steps described in greaterdetail hereafter.

Initially, it is ascertained whether a treatment functionality of thetreatment unit could jeopardize a patient in whom the system wasimplanted if a diagnostic and/or therapeutic treatment of the patientdefined by the treatment functionality were to be carried out.

When such a potential patient risk was ascertained, the treatmentfunctionality is deactivated. It remains in the deactivated statethereof until it is reactivated based on reactivation data.

Such reactivation data can be received by way of the remote datatransmission unit. After the reactivation data has been received, it ispossible to reactivate the previously deactivated treatmentfunctionality.

Thereafter, a diagnostic and/or therapeutic treatment of the patientdefined by the treatment functionality can be carried out.

One aspect of the present invention relates to an implantable system forstimulating a human heart or an animal heart, having the featuresdescribed hereafter. Such a system is intended, in particular, for thepermanent implantation in a human patient or an animal patient. When thesystem is to be implanted in an animal patient, the patient ispreferably a mammal, for example a mammal selected from the groupconsisting of rodents, horses, dogs and cats.

The system comprises a processor, a memory unit, an atrial stimulationunit, and a detection unit for detecting atrial tachycardia.

According to the invention, it is provided that the memory unitcomprises a computer-readable program, which prompts the processor tocarry out the steps described hereafter when the program is beingexecuted on the processor.

First, it is detected by way of the detection unit whether atrialtachycardia to be treated is present in a human heart or an animalheart.

When such atrial tachycardia to be treated was detected, atrialantitachycardia pacing is applied by way of the atrial stimulation unit.

After the atrial antitachycardia pacing has been applied, an atrialpost-treatment stimulation is carried out. In particular, the atrialstimulation unit is likewise used for this purpose. The post-treatmentstimulation causes a change in the cardiac state, whereby the long-termtherapy success rate of the atrial overstimulation, which was carriedout within the scope of the atrial antitachycardia pacing, is increased.As a result of the atrial post-treatment, overall a sustained effect ofthe atrial antitachycardia pacing therapy is achieved. The reason isthat the treated heart, as a result of the atrial post-treatment, has alesser tendency toward returning into a state of atrial tachycardia.

In one variant, the program prompts the processor, after the atrialantitachycardia pacing has been applied, to initially check by way ofthe detection unit whether the atrial tachycardia was terminated by theconducted stimulation. Thus, a termination detection of the atrialtachycardia is carried out. Only when the termination of the atrialtachycardia was positively ascertained is the atrial post-treatmentstimulation carried out. In this way, it is achieved that the atrialpost-treatment stimulation is carried out at a point in time at whichthe treated heart no longer requires atrial antitachycardia pacing forterminating the previously detected atrial tachycardia.

In one variant, the program prompts the processor to carry out theatrial post-treatment stimulation as atrial overstimulation. This atrialoverstimulation is delimited with respect to the atrial antitachycardiaoverstimulation by being designed to be longer than atrialantitachycardia overstimulation, that is, in the range of minutes up todays. According to one embodiment, the atrial post-treatment is designedto be within a range of up to 7 days, 6 days, 5 days, 4 days, 3 days, 2days or 1 day. According to further embodiments, the atrialpost-treatment is designed to be within a range of up to 120 minutes, 60minutes, 30 minutes, 20 minutes, 10 minutes, 5 minutes, 4 minutes, 3minutes, 2 minutes, 1 minute or 0.5 minute. Moreover, the atrialpost-treatment stimulation according to the invention differs from theknown antitachycardia overstimulation by only being invoked when notachycardiac intrinsic (heart's own) atrial activity is present, thatis, for example, when the atrial intrinsic heart rhythm is less than 100bpm. According to a particularly advantageous embodiment of theinvention, the atrial post-treatment stimulation is delivered using astimulation rate of less than or equal to 200 bpm, 180 bpm, 150 bpm, 140bpm, 130 bpm, 120 bpm, 110 bpm, or 100 bpm. By comparison, stimulationrates of 375 bpm are used for the known antitachycardia overstimulation,or rates of up to 3000 bpm (50 Hz) in the case of high-frequency bursts.

In one variant, the atrial post-treatment stimulation is carried out inthe form of right atrial overdrive pacing. During such overdrive pacing,the corresponding atrium is stimulated using a rate higher than thecustomary (intrinsic) non-tachycardiac atrial rate. However, thestimulation rate for overdrive pacing is less than for atrialantitachycardia pacing (for example, less than or equal to 130 bpm).

In another variant, the program prompts the processor to carry out theatrial post-treatment stimulation in the form of left atrial overdrivepacing. The atrial post-treatment stimulation can thus deliberatelyinfluence the rate of the atrial rhythm of a single atrium, and inparticular delay the return from a tachycardia state into a normalstate.

In another variant, it is provided that the atrial post-treatmentstimulation is designed as biatrial overdrive pacing. In such a case,the program prompts the processor to increase the atrial rate of therhythm of both atria.

Such an overdrive post-treatment of one or both atria brings the heartmore slowly back into the normal state after atrial antitachycardiapacing than if no post-treatment stimulation were carried out. As aresult, a gentle transition between atrial antitachycardia pacing andthe normal heart rhythm is achieved, which results in a mild treatmentof the heart and ensures a more sustained effect of the atrialantitachycardia pacing therapy.

In one variant, the program prompts the processor to carry out theatrial post-treatment stimulation during a first duration. This firstduration is specifiable in the process. It is thus a defined time periodin a range of 1 minute to 7 days.

In one variant, the atrial post-treatment stimulation is not carried outfor a (fixed) time period, but uses the heart rhythm of the treatedpatient for reference. In this variant, the program thus prompts theprocessor to carry out the atrial post-treatment stimulation during adefined number of cardiac cycles. In this variant, it is possible toaddress the different heart rhythms of the individual patients even morespecifically, which can further enhance the lasting success of thepost-treatment stimulation.

In one variant, the program prompts the processor to carry out theatrial post-treatment stimulation in a manner that achieves a particularphysiological objective. For example, the post-treatment stimulation canbe carried out in such a way that the pressure in the left and/or rightatrium is lowered at least briefly. As an alternative or in addition,the post-treatment stimulation can be carried out in such a way that therisk of mitral valve regurgitation is reduced at least briefly orentirely avoided. As an alternative or in addition, the post-treatmentstimulation can be carried out in such a way that the preload of theheart is reduced at least briefly. As an alternative or in addition, thepost-treatment stimulation can be carried out in such a way that theblood pressure of a patient whose heart is being stimulated by theimplantable system is lowered at least briefly. As an alternative or inaddition, the post-treatment stimulation can finally be carried out insuch a way that a myocardial oxygen balance is improved at leastbriefly. All of these effects—either individually or in any arbitrarycombination—achieve a change in the cardiac state, which increases thelasting effect of the previously applied atrial antitachycardia pacing,and thereby improves the success of the atrial antitachycardia pacingtherapy.

In one variant, the atrial stimulation unit is designed to apply theatrial antitachycardia pacing and/or the atrial post-treatmentstimulation in the form of electrical stimulation or in the form ofoptical stimulation. In this way, it is possible to apply not only theatrial antitachycardia pacing therapy, but also the atrialpost-treatment stimulation, by employing different physical mechanismsof action. The different available treatment variants can, inparticular, be selected by taking the severity of the detected atrialtachycardia, and the resultant post-treatment stimulation that is usefulto carry out, into consideration.

One aspect of the present invention relates to a method for controllingthe operation of an implantable system for stimulating a human heart oran animal heart. This method is suitable, in particular, for controllingthe operation of an implantable system according to the abovedescriptions. This control method comprises the steps describedhereafter.

First, it is detected by way of a detection device whether atrialtachycardia to be treated is present in a human heart or an animalheart.

When such atrial tachycardia to be treated was detected, at least oneimpulse for atrial antitachycardia pacing is generated in an atrialstimulation unit.

After the impulse for the atrial antitachycardia pacing therapy has beengenerated, at least one impulse for an atrial post-treatment stimulationis generated in the atrial stimulation unit. Previously, it can bechecked whether atrial tachycardia to be treated is still present in thehuman or animal heart. The generation of the at least one impulse forthe atrial post-treatment stimulation can be made dependent on whether atermination of previously detected atrial tachycardia requiringtreatment was ascertained. An appropriate detector signal can serve asan input variable for the control method for this purpose.

One aspect of the present invention relates to a computer programproduct including computer-readable code, which prompts a processor tocarry out the steps described hereafter when the code is being executedon the processor.

First, it is detected by way of a detection device whether atrialtachycardia to be treated is present in a human heart or an animalheart.

When such atrial tachycardia to be treated was detected, atrialantitachycardia pacing is carried out by way of an atrial stimulationunit.

After the atrial antitachycardia pacing has been applied, in particularlikewise by way of the atrial stimulation unit, an atrial post-treatmentstimulation is carried out.

One aspect of the present invention relates to a method for treating ahuman patient or an animal patient in need of such treatment. Animplantable system for stimulating the heart of the patient is used inthe process. This system comprises a processor, a memory unit, an atrialstimulation unit, and a detection unit for detecting atrial tachycardia.The treatment method comprises the steps described hereafter.

First, it is checked by way of the detection unit whether atrialtachycardia to be treated is present in the heart of the patient.

When such atrial tachycardia was detected, atrial antitachycardia pacingis applied by way of the atrial stimulation unit.

After the atrial antitachycardia pacing has been applied, an atrialpost-treatment stimulation is carried out. This atrial post-treatmentstimulation brings the heart of the patient more slowly into a normalstate having a common heart rhythm than if the atrial antitachycardiapacing therapy were ended abruptly. As a result of this gentlertransition to a common heart rhythm, a sustained and longer lastingeffect of the applied atrial antitachycardia pacing therapy is achieved.

All variants and alternative embodiments described in connection withthe various implantable systems can be arbitrarily combined with oneanother and applied to the respective other systems. Similarly, they canalso be applied in arbitrary combination to the described methods andthe described computer program products. The described variants of themethods can further be arbitrarily combined with one another and appliedto the respective other methods and to the computer program products andthe systems. Similarly, the described variants of the computer programproducts can be arbitrarily combined with one another and applied to therespective other computer program products and to the described methodsand the described systems.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin implantable system for stimulating a human heart or an animal heart,it is nevertheless not intended to be limited to the details shown,since various modifications and structural changes may be made thereinwithout departing from the spirit of the invention and within the scopeand range of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram of an exemplary embodiment of an implantablesystem for stimulating a human heart or an animal heart;

FIG. 2 is a schematic flow chart of an exemplary embodiment of an atrialantitachycardia therapy;

FIG. 3 is a schematic illustration of an arrangement of multipleelectrodes in the human heart;

FIG. 4 is a schematic illustration of a chronological progression of anexemplary embodiment of a cardiac treatment;

FIG. 5 is a flow diagram of an exemplary embodiment of the cardiactreatment;

FIG. 6 is a simplified block diagram of an exemplary embodiment of asystem for treating the human or animal heart;

FIG. 7 is a block diagram of an exemplary embodiment of a treatmentsystem for a diagnostic and/or therapeutic treatment of a patient;

FIG. 8 is a flow diagram of a schematic flow of an exemplary methodcarried out by an exemplary embodiment of an implantable system for thediagnostic and/or therapeutic treatment of a patient;

FIG. 9 is a block diagram of an exemplary embodiment of the implantablesystem for stimulating the human heart or the animal heart;

FIG. 10 is a schematic flow chart of an exemplary embodiment of anatrial antitachycardia therapy;

FIG. 11 is a block diagram of an exemplary embodiment of the implantablesystem for stimulating the human heart or the animal heart;

FIG. 12 is a schematic flow chart of an exemplary embodiment of adetection of a cardiac rhythm disturbance; and

FIG. 13 is a schematic flow chart of an exemplary embodiment of atreatment of a cardiac rhythm disturbance by way of stimulation,including upstream detection of the cardiac rhythm disturbance.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figures of the drawings in detail and first,particularly to FIG. 1 thereof, there is shown a block diagram of anexemplary embodiment of a cardiac pacemaker 100, which is used as animplantable system for stimulating the human or animal heart. Thecardiac pacemaker 100 comprises a power source 110, a first detectionunit 120, an atrial stimulation unit 130, a second detection unit 140,and a ventricular stimulation unit 150. The first detection unit 120,the atrial stimulation unit 130, the second detection unit 140 and theventricular stimulation unit 150 are operatively connected to a controlunit 160. A processor 170 and a memory 180 are assigned to the controlunit 160. The memory 180 includes program information prompting theprocessor 170 to carry out certain steps when the program is beingexecuted on the processor 170.

These steps provide that it is detected by way of the first detectionunit 120 whether atrial tachycardia to be treated is present in a humanheart or an animal heart. When such atrial tachycardia requiringtreatment is identified, the processor 170 prompts the ventricularstimulation unit 130 by way of the control unit 160 to carry out aventricular conditioning stimulation of one ventricle or bothventricles. The effect of this ventricular conditioning stimulation isoptionally detected by the second detection unit 140 and communicated tothe processor 170 via the control unit 160. As the ventricularconditioning stimulation is being carried out by the ventricularstimulation unit 130 and/or thereafter, the processor 170, together withthe control unit 160, ensures that the atrial stimulation unit 150applies antitachycardia pacing to the (right) atrium of the heart to betreated.

The energy required for the operation of the individual components ofthe cardiac pacemaker 100 is provided by the power source 110.

FIG. 2 shows the schematic flow chart of an exemplary embodiment of anatrial therapy, which can be carried out, for example, by way of thecardiac pacemaker 100 of FIG. 1.

In a first step, continuous rhythm monitoring 210 of the atrial rhythmof the patient wearing the cardiac pacemaker is carried out. If atrialtachycardia requiring treatment is established in a decision-making step220 within the scope of this atrial rhythm monitoring 210, a ventricularpretreatment 230 is carried out. In FIG. 2 and in all figures thatfollow, the letter “n” denotes a negative decision or a negative resultof a previously conducted check, whereas the letter “y” denotes apositive decision or a positive result of a previously conducted check.

The ventricular pretreatment 230 can be designed in the form ofventricular pacing, for example, which is triggered by every otheratrial excitation and is delivered with a short AV delay of 10 ms, forexample. A ventricular contraction is then already initiated in a phasewhere ventricular filling is still reduced. This ventricular contractionis thus carried out under reduced preload, so that a negative inotropiceffect is achieved, briefly resulting in a reduced systemic bloodpressure. The reduction in blood pressure thus generated increases thesuccess of a concurrently or subsequently applied atrial ATP therapy.

The ventricular conditioning stimulation (ventricular pretreatment) isinitially set until an established pretreatment time has been reached.It is thus checked in a checking step 240 whether the establishedpretreatment time has already been reached. If this is the case, atrialATP 250 is subsequently delivered. After delivery of the atrial ATP 250,a post-ATP treatment 260 may optionally be carried out. As analternative, the cardiac pacemaker can return or be reset to thecontinuous rhythm monitoring 210 again immediately after delivery of theatrial ATP 250.

FIG. 3 shows a thorax 300 of a human patient, in whom a cardiacpacemaker was implanted as a system for treating the heart, toillustrate the functional principle of an electrode positiondetermination. A heart 310 is schematically illustrated in a centralregion of the thorax 300. The heart 310 includes different cardiacregions 320, 321 and 322. This can be the left or right ventricle or anatrium of the heart 310, for example. A first electrode 330 is disposedin the first cardiac region 320. A second electrode 331 is disposed inthe second cardiac region 321. Finally, a third electrode 332 disposedin the third cardiac region 322. The first electrode 330, the secondelectrode 331 and the third electrode 332 each include a conductingsection 340, 341 and 342, which is disposed at the respective end andcan also be referred to as an electrode pole.

Moreover, a fourth electrode 333, which likewise comprises a conductingsection 343 at the end, is disposed outside the heart 310 in the regionof the thorax 300.

A first distance 350 between the first electrode pole 340 of the firstelectrode 330 and the second electrode pole 341 of the second electrode331 can now be determined. Similarly, a second distance 351 between thesecond electrode pole 341 of the second electrode 331 and the thirdelectrode pole 342 of the third electrode 332 can be determined.Moreover, a third distance 352 between the first electrode pole 340 ofthe first electrode 330 and the third electrode pole 342 of the thirdelectrode 332 can be determined. Likewise, it is possible to determine adistance between each of the electrode poles 340, 341, 342 and thereference electrode pole 343 of the reference electrode 342. Such afourth distance 353 is only shown by way of example in FIG. 3 for thedistance between the second electrode pole 341 of the second electrode331 and the reference electrode pole 343 of the reference electrode 333.

The first electrode 330, the second electrode 331 and/or the thirdelectrode 332 are only used for a cardiac treatment when the distances350, 351, 352 and/or 353 are within predefinable ranges. If, incontrast, one of the ascertained distances 350, 351, 352 and/or 353 istoo small or too large, a cardiac treatment is initially not carried outsince the position of at least one electrode is inadequate.

FIG. 4 schematically shows the chronological progression of a cardiactreatment, in which first the position of a treatment electrode ischecked. The events taking place are shown on a time axis 400. A therapytrigger 410 plans a specific cardiac therapy 420, which can also bereferred to as cardiac treatment. This cardiac therapy 420 is planned bythe therapy trigger 410 because previously a cardiac event which wasclassified as requiring treatment was established by way of a detectionunit. Prior to the delivery of the cardiac therapy 420, however, it ischecked during a time period 430 whether the positions of the electrodesrequired for the cardiac therapy 420 (see FIG. 3 in this regard) areadequate for the cardiac therapy 420. Only if this is the case is thecardiac therapy 420 actually carried out. Otherwise, the cardiac therapy420 is at least initially suppressed from being conducted.

FIG. 5 shows a flow diagram of a schematic flow of a method for treatinga human heart or an animal heart, in which correct electrode positioningis checked before a cardiac therapy is carried out. In a first step,continuous rhythm monitoring 500 of the heart rhythm of the patient iscarried out. If a cardiac event requiring treatment is established inthe process, a position determination 520 of at least one treatmentelectrode of a cardiac pacemaker is initiated after a firstdecision-making step 510. Within the scope of this positiondetermination 520, it is ascertained whether the position of thetreatment electrode agrees with a predefinable reference position.

If it is established in a second decision-making step 530 that theposition agrees with the reference position, a cardiac treatment 540 canbe carried out, using the treatment electrode. If, in contrast, it isascertained in the second decision-making step 530 that the establishedposition of the treatment electrode does not agree with the expectedposition, the cardiac pacemaker is transferred into a wait mode 550. Thecardiac pacemaker can be transferred from this wait mode 550 back intocontinuous rhythm monitoring 500. As an alternative, it is also possibleto trigger a cardiac treatment manually, for example.

FIG. 6 shows a simplified block diagram of an implantable cardiacpacemaker 600, which carries out a position determination of at leastone treatment electrode. The cardiac pacemaker 600 serves as animplantable system for treating a human heart or an animal heart. Itcomprises a control unit 610, which is equipped with a processor 611 anda memory unit 612. A detection unit 620 checks whether a cardiac eventto be treated has occurred in the human or animal heart of the patientin whom the cardiac pacemaker 600 was implanted. The detection unit 620transmits the result of this check to the control unit 610.

When a cardiac event to be treated has occurred, the processor 611prompts a position check unit 630, by way of the control unit 610, tocheck the position of a treatment electrode 640. For this purpose, theposition check unit 630 compares the established position of theelectrode 640 to a reference position. Additional data, which providesinsights into the position of the treatment electrode 640, using anadditional position sensor or acceleration sensor 650 can be used in theprocess.

The data provided by the position determination unit 630, and optionallyby the additional sensors 650, is evaluated in an analysis unit 660. Ifit is found in the process that the position of the treatment electrode640 corresponds to a position adequate for the impending cardiactherapy, the processor 611, by way of the control unit 610, activates atherapy unit 670, which delivers a therapy adequate for treating thecardiac event to the corresponding cardiac region by way of thetreatment electrode 640.

The data regarding the position of the treatment electrode 640 collectedby the position determination unit 630 can be stored, together with apiece of time information, in a trend memory 680 so as to be able toevaluate or identify a trend of the change in position of the treatmentelectrode 640.

When the analysis unit 660 establishes an inadequate position of thetreatment electrode 640, the therapy unit 670 is not activated for thedelivery of a cardiac treatment. Rather, initially no cardiac treatmentis carried out.

The treatment electrode 640 can moreover simultaneously act as adetection electrode and thus already be used together with the detectionunit 620 in the detection of a cardiac event to be treated.

Not all units shown in the block diagram of FIG. 6 necessarily have toform separate units within the cardiac pacemaker 600. Rather, theprocessor 611 can assume numerous tasks if it receives appropriateprogram information from the memory 612.

FIG. 7 shows an exemplary embodiment of a treatment system 700comprising an implant 705, which serves as an implantable system for thediagnostic and/or therapeutic treatment of a human patient or an animalpatient. The implant 705 comprises a first control unit 710 including afirst processor 711 and a first memory unit 712. Furthermore, adetection unit 720 is provided, which checks a particular physiologicalparameter of a patient in whom the implant 705 is implanted. Forexample, a heart rhythm of the patient can be monitored by the detectionunit 720. In addition, the implant 705 comprises a treatment unit 730,which can be used to carry out a diagnostic and/or therapeutic treatmentof the patient. This treatment unit 730 includes a plurality ofdifferent treatment functionalities, which each define a particulartreatment. A treatment functionality may also specify a sequence ofcertain diagnostic and/or therapeutic treatments.

The implant 705 furthermore comprises a first remote data transmissionunit 740 by way of which data can be transmitted and/or received by thecontrol unit 710 or the processor 711. The remote data transmission unit740 preferably operates wirelessly.

In addition, the treatment system 700 comprises a remote access unit750, which is disposed remotely from the implant 705. The remote accessunit 750 can be set up in a hospital or a doctor's office, for example.By way of the remote access unit 750, it is possible to establishcommunications contact with the implant 705. For this purpose, theremote access unit 750 comprises a second processor 760, a second memoryunit 770, a user interface 780 and a second remote data transmissionunit 790.

The second processor 760 is able to retrieve program information fromthe second memory unit 770 so as to subsequently carry out acorresponding program. By way of the user interface 780, it is possibleto carry out inputs for the further processing of data by the secondprocessor 760. For example, a physician can manually prompt areactivation of a previously deactivated treatment functionality by wayof the user interface 780. The second processor 760 can then transmitreactivation data to the first data transmission unit 740 of the implant705 via the second remote data transmission unit 790. When the firstprocessor 711 of the implant 705 receives such reactivation data, it canforward this data to the treatment unit 730 and reactivate a previouslydeactivated treatment functionality of the treatment unit 730.

The implant 705 and the remote access unit 750 can be disposed severalmeters, several kilometers, but also hundreds or thousands of kilometersapart from one another. By selecting appropriate data transmissionprotocols, reliable communication between the first data transmissionunit 740 disposed in the implant 705 and the second remote datatransmission unit 790 disposed in the remote access unit 750 cannonetheless be ensured.

FIG. 8 shows a flow chart to schematically illustrate an exemplary flowof a method that can be carried out by an exemplary embodiment of animplantable system for the diagnostic and/or therapeutic treatment of ahuman patient or an animal patient, such as by the implant 705 of FIG.7.

This flow chart refers to the specific application in the field ofatrial antitachycardia pacing. This means that it is assumed, within thescope of the exemplary embodiment illustrated in FIG. 8, that theimplant is a cardiac pacemaker, that is, a system for stimulating thehuman heart or animal heart.

In a first step 800, it is checked whether the delivery of an atrialantitachycardia therapy is activated. Such a delivery of an atrialantitachycardia therapy represents a treatment functionality that thetreatment or stimulation unit of the corresponding implant can carryout. If it is established during this check that the delivery of anatrial antitachycardia therapy is cleared, such an atrialantitachycardia therapy 810 can be delivered.

After expiration of a presettable time, which is 48 hours in theexemplary embodiment described here, the further delivery of atrialantitachycardia pacing is suppressed. The reason is that, if atrialantitachycardia pacing is required over such an extended time period,the patient's risk of thrombosis increases as a result of the atrialtachycardia still not being successfully treated. The patient now has tovisit his or her primary care physician for a medical examination 820.The patient receives an anticoagulation drug therapy within the scope ofthis examination. The administration of anticoagulation pharmaceuticalslowers the patient's risk of thrombosis again. This information that thepatient received such an anticoagulation therapy is forwarded to animplantation physician, that is, a physician specialized in implants,such as cardiac pacemakers. This implantation physician can thenreactivate the option of delivering of an atrial antitachycardia pacingtherapy within the scope of a clearance 830 by way of remote access. Forthis purpose, the physician transmits clearance data to the cardiacpacemaker of the patient, which results in a reactivation of thedeactivated treatment functionality.

It is then possible to deliver atrial antitachycardia pacing therapiesagain, should this still be necessary based on the state of thepatient's heart. In the event that the atrial heart rhythm of thepatient has since normalized again, the option of delivering atrialantitachycardia pacing therapies nonetheless remains activated. Ifatrial tachycardia reoccurs, a corresponding atrial antitachycardiatreatment can then be carried out.

FIG. 9 shows a block diagram of an exemplary embodiment of a cardiacpacemaker 900, which is used as an implantable system for stimulatingthe human or animal heart. The cardiac pacemaker 900 comprises a powersource 910 which supplies the individual components of the cardiacpacemaker 900 with electric energy. Moreover, the cardiac pacemaker 900comprises a detection unit 920, an atrial stimulation unit 930 and acontrol unit 940, which is operatively connected to both the detectionunit 920 and the atrial stimulation unit 930. A processor 950 and amemory unit 960, which are operatively connected to one another, areassigned to the control unit 940. The memory unit 960 includes programinformation prompting the processor 950 to carry out certain steps whenthe program is being executed on the processor 950.

In the specific case of the exemplary embodiment of FIG. 9, theprocessor 950 retrieves program information from the memory unit 960,which prompts the processor first to query information from thedetection unit 920 as to whether atrial tachycardia was detected in ahuman heart or an animal heart. When this is the case, the processorprompts the atrial stimulation unit 930 to apply atrial antitachycardiapacing to the affected atrium. Thereafter, the processor 950 prompts theatrial stimulation unit 930 to carry out an atrial post-treatmentstimulation so as to increase the effect of the applied atrialantitachycardia pacing therapy. For this purpose, the processor 950 caninitially retrieve additional information from the detection unit 920 asto whether the previously detected atrial tachycardia was terminated bythe atrial antitachycardia pacing that was already applied. Theprocessor can suspend the atrial post-treatment stimulation from beingcarried out by way of the atrial stimulation unit 930 until positiveinformation was ascertained on the part of the detection device 920 withrespect to a termination of the previously detected atrial tachycardia.

FIG. 10 shows a schematic flow chart of an exemplary embodiment of anatrial therapy, which can be carried out, for example, by way of thecardiac pacemaker 900 of FIG. 9.

In a first step, continuous rhythm monitoring 1010 of the atrial rhythmof a patient wearing the cardiac pacemaker is carried out. If it isestablished in a decision-making step 1020, within the scope of thisatrial rhythm monitoring 1010, that atrial tachycardia requiringtreatment is present, atrial antitachycardia pacing 1030 is subsequentlyapplied or delivered, which can also be referred to as atrial ATP.Afterwards, an atrial post-treatment 1040 is carried out, which can alsobe referred to as ATP post-treatment. This post-treatment is carried outusing a lower stimulation rate than for the atrial antitachycardiapacing 1030, but the rate is still greater than the normal (intrinsic)atrial heart rate.

After completion of the atrial post-treatment stimulation 1040, thecardiac pacemaker is returned into a mode of continuous rhythmmonitoring 1010. The decision as to when the atrial post-treatmentstimulation 1040 is ended can be made, for example, as a function of anelapsed time or as a function of a certain number of cardiac cycles ofthe patient.

FIG. 11 shows a block diagram of a cardiac pacemaker 1100, which servesas an implantable system for stimulating the human or animal heart. Thecardiac pacemaker 1100 comprises a power source 1110, an atrialdetection unit 1120, an atrial stimulation unit 1130, a ventriculardetection unit 1140, a ventricular stimulation unit 1150 and a controlunit 1160. A processor 1170 and a data memory 1180 are assigned to thecontrol unit 1160. The processor 1170 is able to retrieve data from thedata memory 1180, for example so that a program can be executed on theprocessor 1170. The atrial detection unit 1120, the atrial stimulationunit 1130, the ventricular detection unit 1140 and the ventricularstimulation unit 1150 are operatively connected to the control unit1160, so that the processor is able to receive signals from theindividual units or send signals to the individual units.

A success or an efficiency of a stimulation previously carried out byway of the atrial stimulation unit 1130 or the ventricular stimulationunit 1150 can be stored in the data memory 1180. Typically, thestimulation strategy underlying the corresponding stimulation and thecardiac rhythm disturbance previously detected by the atrial detectionunit 1120 and/or the ventricular detection unit 1140 are also stored. Inaddition, it is possible to assign a priority criterion to theindividual data sets comprising the detected cardiac rhythm disturbance,the applied stimulation strategy and the achieved success or achievedefficiency, and to store this together with the data sets. In this way,it is possible to assign a higher priority to data sets that relate to aparticularly successful or particularly efficient stimulation.

FIG. 12 shows a schematic flow chart for a method which can be used todistinguish different cardiac rhythm disturbances from one another. Thismethod can be carried out by a cardiac pacemaker, such as the cardiacpacemaker 1100 of FIG. 11.

In a first step 1210, continuous rhythm monitoring of the atrial heartrhythm of the patient in whom the corresponding cardiac pacemaker wasimplanted is carried out. When atrial tachyarrhythmia or atrialtachycardia is established within the scope of this continuous rhythmmonitoring 1210 in a decision-making step 1220, additionally monitoring1230 of the ventricular rhythm of the patient is carried out.

In a subsequent decision-making step 1240, a more detailed analysis ofthe detected atrial rhythm and of the detected ventricular rhythm withrespect to the resulting heart rhythm and the atrioventricularconduction (AV conduction) takes place. The resulting heart rhythm isdivided into three rhythm categories 1250, 1260 and 1270. The firstrhythm category 1250 encompasses a presence of VT or also of VT withretrograde conduction. The second rhythm category 1260 encompassesatrial tachycardia/tachyarrhythmia (AT) and atrial fibrillation (AFib).The third rhythm category 1270 encompasses anterograde conduction ofatrial tachycardia/tachyarrhythmia and supraventricular tachycardia(SVT).

Only when a resulting heart rhythm of the second category 1260 wasdetected, that is, a heart rhythm that encompasses atrialtachycardia/tachyarrhythmia or atrial fibrillation, is a stimulationstrategy subsequently selected which includes atrial antitachycardiapacing. The details of the delivery of this atrial antitachycardiapacing therapy are shown in greater detail in FIG. 13.

The upper portion of FIG. 13 initially shows the method steps which arealready known from FIG. 12. The reference numerals used already in FIG.12 are used again in the process. Reference is made to the abovedescription of FIG. 12 with respect to a more detailed description.

When a heart rhythm of the second category 1260 is identified in thecategorization of the resulting heart rhythm, that is, a heart rhythmthat encompasses atrial tachycardia or atrial fibrillation, a workflowfor atrial antitachycardia pacing is activated 1310.

Initially, at least one measurement variable, namely a physiologicalmeasurement variable of the patient and/or a pathophysiologicalmeasurement variable of the patient, and/or a non-physiologicalmeasurement variable indicating a condition of the patient, isascertained 1320. This may be a measurement variable that specifies thebody position of the patient, for example. This measurement variable ora variable calculated from this measurement variable would then be usedto form a selection criterion. This selection criterion, in the broadestsense, takes the state of health of the patient into consideration.

Thereafter, it is checked in a checking step 1330 whether the conditionor the state of health of the patient meets the fundamental requirementsfor a stimulation. It is thus checked whether suitable stimulationstrategies exist for the formed selection criterion. If this is not thecase, (initially) no pacing is applied. Additional measurement variablescan then be detected so as to characterize the condition of the patientin even more detail and form a new selection criterion.

When the measurement variable or the measurement variables that wereused for the selection criterion show that the patient meets thenecessary requirements for the impending atrial antitachycardia pacingtherapy, the overstimulation therapies available in the internal datamemory of the cardiac pacemaker are retrieved in a subsequent selectionstep 1340. In a further selection step 1350, the stimulation strategiesthat best meet the conditions or measurement variables of the patientascertained in the ascertainment step 1320 are then selected from theavailable overstimulation therapies or stimulation strategies. So as toascertain which stimulation strategies best correspond to the previouslyascertained measurement variable, in particular the form, the design andthe composition of the available stimulation strategies are taken intoconsideration. Moreover, the success rate during prior applications ofthe stimulation strategies can be taken into consideration. The selectedstimulation strategy or strategies is or are then delivered to thepatient in a stimulation delivery step 1360, wherein the sequence of thedelivered stimulations results from the prior prioritization thereof.

In a further checking step 1370, it is subsequently checked whether theconducted stimulation(s) has/have resulted in a termination of theatrial tachycardia. If this is not the case, a change is made in anoptimization step 1380 to the previously conducted stimulation strategyor to the selected stimulation strategies still to be conducted. Thisadaptation is made based on a parameter, such as the treatment form, thetreatment number, the combination of different treatments, the treatmentfrequency and the treatment point in time. It is also noted in theinternal data memory of the cardiac pacemaker that the non-adaptedstimulation strategy was not successful. The priority value thereof islowered in this connection. This means that the priority of thisstimulation strategy is decreased. In contrast, the priority value ofthe adapted (that is, optimized) stimulation strategy can initiallyremain unchanged. When it was ascertained that a successful terminationof the previously detected atrial tachycardia is possible by theoptimized stimulation strategy, the priority criterion of thecorresponding stimulation strategy can be increased. This stimulationstrategy is then preferably applied during a later treatment.

Finally, when it was established in the decision-making step 1370 that atermination of the atrial tachycardia has taken place, this success isstored, together with the details of the applied stimulation strategy(in particular the stimulation form, stimulation design and stimulationcomposition) and the underlying selection criterion or the measurementvariables defining the selection criterion, in the internal data memoryof the cardiac pacemaker. In addition, the information that thisstimulation strategy was successful is stored there. Moreover, thisstimulation strategy is assigned a higher priority value. This takesplace in the memory step 1390. Thereafter, the cardiac pacemaker isreturned into a mode of continuous rhythm monitoring 1210.

As a result of a suitable categorization of a detected cardiac rhythmdisturbance, a selection of suitable stimulation strategies based onmeasurement variables related to the condition of the patient, and aprioritization and an optimization of the different stimulationstrategies, ultimately an extremely efficient treatment of cardiacrhythm disturbances can be carried out. This treatment has aconsiderably lower energy requirement than the treatments known from theprior art. The reason is that stimulation strategies that are not verypromising for the respective detected cardiac rhythm disturbance are notapplied to begin with, as a result of an optimization and prioritizationof different stimulation strategies. This reduces the energy expenditureof the corresponding cardiac pacemaker and thereby extends the servicelife thereof.

It will be apparent to those skilled in the art that numerousmodifications and variations of the described examples and embodimentsare possible in light of the above teaching. The disclosed examples andembodiments are presented for purposes of illustration only. Otheralternate embodiments may include some or all of the features disclosedherein. Therefore, it is the intent to cover all such modifications andalternate embodiments as may come within the true scope of thisinvention.

1. An implantable system for stimulating a heart including a human heartor an animal heart, the implantable system comprising: a processor; astimulator; a first detector for detecting a cardiac rhythm disturbanceof a cardiac region; and a memory storing a computer-readable programprompting said processor to carry out the following steps when thecomputer-readable program is being executed on said processor: detectingby way of said first detector whether the cardiac rhythm disturbance ispresent in the cardiac region of the heart of a patient; selecting astimulation strategy based on a selection criterion when the cardiacrhythm disturbance is present, the selection criterion including ameasurement variable or a variable calculated from the measurementvariable, the measurement variable being selected from the groupconsisting of a physiological measurement variable of the patient, apathophysiological measurement variable of the patient, and anon-physiological measurement variable indicating a state of thepatient; stimulating the cardiac region in which the cardiac rhythmdisturbance was detected by way of said stimulator, using a selectedstimulation strategy; detecting a success and/or an efficiency of aconducted stimulation; comparing the success and/or the efficiency ofthe conducted stimulation to a predefinable success and/or efficiencycriterion; and optimizing the selected stimulation strategy so as toachieve better success and/or greater efficiency during a subsequentstimulation using an optimized stimulation strategy if the predefinablesuccess and/or efficiency criterion was not achieved, an optimizationincluding a change in the stimulation strategy with respect to at leastone parameter, which is selected from the group consisting of a form ofa treatment, a number of treatments, a combination of differenttreatments, a frequency of the treatments, and a point in time of thetreatment; wherein the form of the treatment includes a design of astimulation and/or a pattern of the stimulation; and wherein thestimulation strategy is atrial antitachycardia pacing or cardioversion.2. The implantable system according to claim 1, wherein the measurementvariable is or provides a hemodynamic measurement variable of thepatient, an amplitude of an intracardiac electrogram, an amplitude of afar field signal, an amplitude of an electrocardiogram signal, anamplitude of an atrial signal, a systemic blood pressure, an arterialblood pressure, a venous blood pressure, a blood pressure in aventricle, a pulmonary arterial pressure, another blood pressure or achange in one of the aforementioned blood pressures, a change in amorphology of a detected signal, an impedance change of a detectedsignal, a measurement value allowing a conclusion of a regularity orirregularity of a heart rhythm of the patient, or a body position. 3.The implantable system according to claim 1, wherein the measurementvariable is a variable that can be ascertained by the implantable systemitself or by way of said first detector or a further detector.
 4. Theimplantable system according to claim 1, wherein the efficiency of theconducted stimulation represents a physiological efficiency and/or anenergetic efficiency with respect to energy expended for the conductedstimulation.
 5. The implantable system according to claim 1, wherein thecomputer-readable program prompts said processor to store the selectioncriterion, an applied stimulation strategy and an achieved successand/or an achieved efficiency in said memory, and to prioritize storedstimulation strategies as a function of the achieved success and/or theachieved efficiency.
 6. The implantable system according to claim 5,wherein the computer-readable program prompts said processor to excludea low-priority stimulation strategy, for a first duration, from thestimulation strategies to be selected for an impending stimulation. 7.The implantable system according to claim 1, wherein the stimulationstrategy is atrial antitachycardia pacing or cardioversion.
 8. Theimplantable system according to claim 1, wherein when the detectedcardiac rhythm disturbance is atrial tachycardia, the computer-readableprogram prompts said processor to determine a ventricular cardiac rhythmand to assess the ventricular cardiac rhythm with respect to a risk ofretrograde conduction of ventricular tachycardia in at least one of anatria, and to adapt an atrial antitachycardia pacing therapy withrespect to a location and/or time of an application as a function of anascertained risk.
 9. The implantable system according to claim 1,wherein said stimulator is configured to carry out the stimulation in aform of electrical stimulation or in a form of optical stimulation. 10.A method for controlling an operation of an implantable system forstimulating a heart including a human heart or an animal heart, whichcomprises the following steps of: detecting by way of a first detectorwhether a cardiac rhythm disturbance is present in a cardiac region ofthe heart of a patient; selecting a stimulation strategy based on aselection criterion when the cardiac rhythm disturbance is present, theselection criterion including a measurement variable or a variablecalculated from the measurement variable, the measurement variable beingselected from the group consisting of a physiological measurementvariable of the patient, a pathophysiological measurement variable ofthe patient, and a non-physiological measurement variable indicating astate of the patient, wherein the selected stimulation strategy isatrial antitachycardia pacing or cardioversion; generating at least oneimpulse, in a stimulator, for stimulating the cardiac region in whichthe cardiac rhythm disturbance was detected, using a selectedstimulation strategy; comparing data regarding a success and/or anefficiency of a conducted stimulation to a predefinable success and/orefficiency criterion; and optimizing the stimulation strategy so as toachieve better success and/or greater efficiency during a subsequentstimulation using an optimized stimulation strategy if the predefinablesuccess and/or efficiency criterion was not achieved, an optimizationincluding a change in the stimulation strategy with respect to at leastone parameter, which is selected from the group consisting of a form ofa treatment, a number of treatments, a combination of differenttreatments, a frequency of the treatments, and a point in time of thetreatment, wherein the form of the treatment includes a design of astimulation and/or a pattern of the stimulation.
 11. A computer programproduct having computer-readable code prompting a processor to carry outthe following steps when the computer-readable code is being executed onsaid processor: detecting by way of a first detector whether a cardiacrhythm disturbance is present in a cardiac region of a heart of apatient including a human patient or an animal patient; selecting astimulation strategy based on a selection criterion when the cardiacrhythm disturbance is present, the selection criterion including ameasurement variable or a variable calculated from the measurementvariable, the measurement variable being selected from the groupconsisting of a physiological measurement variable of the patient, apathophysiological measurement variable of the patient, and anon-physiological measurement variable indicating a state of thepatient, wherein the selected stimulation strategy is atrialantitachycardia pacing or cardioversion; stimulating the cardiac regionin which the cardiac rhythm disturbance was detected by way of astimulator, using a selected stimulation strategy; detecting a successand/or an efficiency of a conducted stimulation; comparing the successand/or the efficiency of the conducted stimulation to a predefinablesuccess and/or efficiency criterion; and optimizing the stimulationstrategy so as to achieve better success and/or greater efficiencyduring a subsequent stimulation using an optimized stimulation strategyif the predefinable success and/or efficiency criterion was notachieved, an optimization including a change in the stimulation strategywith respect to at least one parameter, which is selected from the groupconsisting of a form of a treatment, a number of treatments, acombination of different treatments, a frequency of the treatments, anda point in time of the treatment, wherein the form of the treatmentincludes a design of a stimulation and/or a pattern of the stimulation.12. A method for treating a patient including human patient or an animalpatient requiring such treatment by way of an implantable system forstimulating a heart of the patient, the implantable system including aprocessor, a memory, a stimulator, and a first detector for detecting acardiac rhythm disturbance of a cardiac region, the method comprises thefollowing steps of: detecting by way of the first detector whether thecardiac rhythm disturbance is present in the cardiac region of the heartof the patient; selecting a stimulation strategy based on a selectioncriterion when the cardiac rhythm disturbance is present, the selectioncriterion including a measurement variable or a variable calculated fromthe measurement variable, the measurement variable being selected fromthe group consisting of a physiological measurement variable of thepatient, a pathophysiological measurement variable of the patient, and anon-physiological measurement variable indicating a state of thepatient, wherein the selected stimulation strategy is atrialantitachycardia pacing or cardioversion; stimulating the cardiac regionin which the cardiac rhythm disturbance was detected by way of thestimulator, using a selected stimulation strategy; detecting a successand/or an efficiency of a conducted stimulation; comparing the successand/or the efficiency of the conducted stimulation to a predefinablesuccess and/or efficiency criterion; and optimizing the stimulationstrategy so as to achieve better success and/or greater efficiencyduring a subsequent stimulation using an optimized stimulation strategyif the predefinable success and/or efficiency criterion was notachieved, an optimization including a change in the stimulation strategywith respect to at least one parameter, which is selected from the groupconsisting of a form of a treatment, a number of treatments, acombination of different treatments, a frequency of the treatments, anda point in time of the treatment, wherein the form of the treatmentincludes a design of a stimulation and/or a pattern of the stimulation.